CN112436852B - Method and device for searching parameters of analog front-end circuit of receiver - Google Patents

Abstract

The embodiment of the application provides a method and a device for searching parameters of an analog front-end circuit of a receiver, wherein the method comprises the following steps: acquiring a plurality of eye pattern values corresponding to interface parameter values of at least part of rows included in a lookup table, wherein each row in the at least part of rows corresponds to one eye pattern value respectively, an analog front end circuit of the receiver includes a plurality of sub-circuits, the interface parameter values of each row in the at least part of rows included in the lookup table include a plurality of columns, and each column corresponds to each sub-circuit in the plurality of sub-circuits respectively; identifying target interface parameter values for the plurality of sub-circuits based on the plurality of eye pattern values and eye pattern thresholds. Some embodiments of the application realize that the setting parameters of a plurality of sub-circuits at the analog front end of the receiving part can be jointly searched at the same time, thereby solving the mutual influence among a plurality of setting parameters and having high efficiency.

Description

A kind of method and apparatus for searching receiver analog front-end circuit parameters

technical field

The present application relates to the field of circuit design, and in particular, the embodiments of the present application relate to a method and an apparatus for searching circuit parameters of an analog front-end of a receiver.

Background technique

In the field of high-speed serial communication, the transmission data rate of non-return-to-zero NRZ (Non-Return-to-Zero) coding can be as high as 33Gbps. At the same time, the attenuation of high-speed data by the transmission channel presents a low-pass characteristic, and the high-frequency components of high-speed data are attenuated. Much larger than the low-frequency component, when the data from the TX transmitter is transmitted to the RX receiver, the eye opening is very small or even closed, which poses a great challenge to the correct reception of RX data.

In order to compensate for the attenuation of the transmission channel, the TX transmitter usually uses a forward feedback equalizer (Feedback Forward Equalizer) circuit to pre-emphasize the current transmission data. The transmission curve of this FFE circuit is a high-pass filter, while the RX receiving front end (that is, receiving (computer analog front-end circuit) will also use a more complex combination of linear and nonlinear equalizer structures. The mainstream receiver analog front-end circuit RX AFE (Analog Front-End,) is generally composed of the following four sub-circuits according to the flow of the analog signal: attenuator ATT (Attenuator), continuous time linear equalizer CTLE (Continuous Time Linear Equalizer), voltage Gain control circuit VGA (Voltage Gain) and decision feedback equalizer DFE (Decision Feedback Equalizer), in which the transmission curves of CTLE and DFE circuits are also high-pass filters.

Therefore, how to set the parameters of the four sub-circuits of the RX AFE to achieve the best compensation for the transmission channel becomes critical and significant.

SUMMARY OF THE INVENTION

The purpose of the embodiments of the present application is to provide a method for searching the parameters of the analog front-end circuit of a receiver. The implementation of the present application can be applied to a high-speed serial communication interface, and provides a fast search and The determination method can simultaneously perform joint search on multiple setting parameters of multiple sub-circuits included in the receiving, ie, analog front-end circuit, so as to solve the mutual influence between multiple setting parameters, and the efficiency is high.

In a first aspect, some embodiments of the present application provide a method for searching analog front-end circuit parameters of a receiver, the method comprising: acquiring a plurality of eye diagram values corresponding to interface parameter values of at least some rows included in a lookup table, Wherein, the interface parameter values of each row in the at least part of the rows correspond to an eye diagram value, the analog front-end circuit of the receiver includes a plurality of sub-circuits, and the interface parameter values of each row of the look-up table include multiple columns, and each column is respectively Corresponding to each sub-circuit in the plurality of sub-circuits; confirming target interface parameter values of the plurality of sub-circuits according to the plurality of eye diagram values and eye diagram thresholds.

Some embodiments of the present application confirm the eye diagram value corresponding to the whole analog front-end circuit after each sub-circuit is set by using the interface parameters of each row through the optional multi-line candidate interface parameters obtained from the look-up table, thereby realizing that the receiving The setting parameters of multiple sub-circuits required by some analog front ends are searched jointly to solve the mutual influence between multiple setting parameters, and the efficiency is high.

In some embodiments, the look-up table includes an initial look-up table, and the initial look-up table is a preset number of 2 ^r according to changes in channel lengths of different engineering applications, where r is greater than or equal to 1 Natural numbers; the acquiring multiple eye diagram values corresponding to the interface parameter values of at least part of the rows included in the look-up table includes: acquiring 2 ^r eye diagram values corresponding to the analog front-end circuit according to the initial look-up table; The confirming the target interface parameter values of the plurality of sub-circuits according to the plurality of eye diagram values and the eye diagram thresholds includes: searching for a maximum eye diagram value from the 2 ^r eye diagram values; confirming the maximum eye diagram value is greater than or equal to the eye diagram threshold; the interface parameter value of the row corresponding to the maximum eye diagram value in the initial lookup table is used as the initial target interface parameter value; determined according to the initial target interface parameter value and the local search eye diagram threshold At least part of the target interface parameter value, wherein the local search eye diagram threshold is not less than the eye diagram threshold. Some embodiments of the present application preliminarily determine the interface parameter value of each sub-circuit through rough search of the look-up table, and then further search by traversing the search range determined based on the preliminarily determined interface parameter value of each sub-circuit and the local search range threshold The interface parameter value with the best eye diagram effect improves the compensation effect of the interface parameter value determined for each sub-circuit on the channel attenuation. In addition, some embodiments of the present application preferentially use the initial lookup table to search for the largest eye diagram value that satisfies the eye diagram threshold condition, and then use the interface parameter of the corresponding row of the largest eye diagram value in the initial lookup table as the search result of the rough search, Since the size of the initial lookup table is small, the search speed of the interface parameter lookup table can be improved. The local fine search process based on the local search eye diagram threshold should be centered on the lookup table corresponding to the initial target interface parameters determined in the rough search process, and the search range should not exceed the difference between the adjacent upper and lower rows of the lookup table.

In some embodiments, the look-up table includes an initial look-up table and an update look-up table, and the initial look-up table is a preset number of 2 ^r tables according to changes in channel lengths of different engineering applications; the obtaining The look-up table includes multiple eye diagram values corresponding to interface parameter values in at least some rows, including: acquiring 2 ^r eye diagram values corresponding to the analog front-end circuit according to the initial look-up table; confirming the target interface parameter values of the plurality of sub-circuits with the eye diagram values and the eye diagram thresholds, including: finding the maximum eye diagram value from the 2 ^r eye diagram values; confirming that the maximum eye diagram value is smaller than the eye diagram value threshold; determining the initial target interface parameter value according to the update look-up table and the eye diagram threshold, wherein the update look-up table is obtained by adding at least one row to the initial look-up table, and the update look-up table contains The channel attenuation that can be compensated by each row of interface parameters included satisfies monotonicity; at least part of the target interface parameters are determined according to the initial target interface parameter value and the local search eye diagram threshold.

Some embodiments of the present application preliminarily determine the interface parameter value of each sub-circuit through rough search of the lookup table, and then further search by traversing the search range determined based on the preliminarily determined interface parameter value of each sub-circuit and the local search range threshold The interface parameter value with the best eye diagram effect improves the compensation effect of the interface parameter value determined for each sub-circuit on the channel attenuation. In addition, in order to avoid the problem that the interface parameters that meet the conditions cannot be found due to the limited size of the initial lookup table, some embodiments of the present application adopt dynamic expansion of the initial lookup table size, that is, obtain and update the lookup table to determine the search result of the rough search interface parameter, The probability of getting a rough search result by looking up the table can be improved.

In some embodiments, the determining at least part of the target interface parameters according to the initial target interface parameter value and the local search eye diagram threshold includes: determining a plurality of search ranges, wherein the number of the search ranges is the same as the number of the search ranges. The number of the multiple sub-circuits is equal; traverse the multiple search ranges to obtain the maximum local eye diagram value; confirm that the maximum local eye diagram value is greater than the local search eye diagram threshold; compare the maximum local eye diagram value with the maximum local eye diagram value The corresponding interface parameter is identified as the at least part of the target interface parameter.

Some embodiments of the present application further determine multiple refined search ranges through preliminary interface parameter values and local search ranges corresponding to the rough search results, so as to find interface parameter values of subcircuits with better eye diagram effects.

In some embodiments, the channel attenuation that can be compensated by each row of interface parameters included in the initial lookup table satisfies monotonicity.

Some embodiments of the present application improve the ease of implementation of the search process by setting the initial lookup table to satisfy a certain monotonicity.

In some embodiments, the target interface parameter includes tap coefficients corresponding to the decision feedback equalizer, and the values of the columns in which the tap coefficients are included in the lookup table are all zero; confirming the target interface parameter values of the plurality of sub-circuits with the value and the eye diagram threshold, including: searching for part of the target interface parameter values according to the plurality of eye diagram values and the eye diagram threshold, wherein the part of the target interface The parameter value does not include the tap coefficient; according to the eye diagram threshold, the partial target interface parameter value and a step value are searched for the tap coefficient, wherein the step value is adjustable.

In some embodiments of the present application, in order to improve the search speed of the interface parameters corresponding to each sub-circuit, first, the tap coefficients corresponding to the decision feedback equalizer are set to zero in the look-up table, and then the determined interface parameters of the remaining sub-circuits and the set The step size further searches for the tap coefficients, which on the one hand improves the search speed, and on the other hand realizes a joint search for the setting parameters of multiple sub-circuits of the analog front-end of the receiving part at the same time (that is, based on the interface parameter values of the remaining sub-circuits determined first. Determine the tap coefficient of the decision feedback equalizer), solve the mutual influence between multiple setting parameters, and have high efficiency.

In some embodiments, the step size value is a multiple of two.

Some embodiments of the present application improve the search speed of multiple sub-circuit interface parameters by setting the step size of the search tap coefficient to be an integer multiple of 2.

In some embodiments, the confirming the target interface parameter values of the plurality of sub-circuits according to the plurality of eye diagram values and the eye diagram thresholds includes: confirming the plurality of eye diagrams obtained after a maximum set number of cycles. The image values are all smaller than the eye diagram threshold; the target interface parameter value is determined according to the exhaustive method of variable step size.

Some embodiments of the present application take into account the convergence and compromise of the method of searching sub-circuit interface parameters through a lookup table, and set the maximum number of cycles and the exhaustion of the variable step size taken when the search result is still not found when the maximum number of cycles is reached. The method can effectively prevent the phenomenon of deadlock and no result at all during the execution of the search method, and shorten the search time.

In some embodiments, the variable step size is a multiple of two.

Some embodiments of the present application improve the search speed of multiple sub-circuit interface parameters by setting the variable step size in the exhaustive method to be an integer multiple of 2.

In some embodiments, the plurality of subcircuits include at least two of: an attenuator ATT, a continuous time linear equalizer CTLE, a voltage gain control circuit VGA, and criterion feedback equalization.

Some embodiments of the present application set at least two of the attenuator ATT, the continuous time linear equalizer CTLE, the voltage gain control circuit VGA and the criterion feedback equalization in the receiver analog front end to improve the compensation characteristics for channel attenuation.

In some embodiments, before acquiring the multiple eye diagram values corresponding to the interface parameter values of at least part of the rows included in the lookup table, the method further includes: confirming that the receiver starts to receive data and that the clock data recovery signal has been locked to the setting specified application data rate.

Some embodiments of the present application avoid invalid searches and waste system resources by judging that the receiver starts to receive the data sent by the transmitter and the signal acquisition clock is ready.

In some embodiments, both the eye diagram threshold and the eye diagram value are indicators used to characterize the size of the eye diagram.

Some embodiments of the present application use an index representing the size of the eye diagram to measure whether the alternative interface parameters can effectively compensate for the attenuation of the channel.

In some embodiments, the eye threshold or the type of eye value includes a figure of merit, a horizontal eye edge indicator, or a vertical eye edge indicator.

Some embodiments of the present application use various eye diagram indicators to make up for the problem of how to measure the result of channel attenuation compensation by the interface parameters of the receiver analog front-end circuit that does not provide a quality factor.

In a second aspect, some embodiments of the present application provide an apparatus for searching analog front-end circuit parameters of a receiver, the apparatus comprising: an eye diagram value acquisition module configured to acquire an interface for at least part of rows included in a lookup table a plurality of eye diagram values corresponding to the parameter values, wherein each of the at least partial rows corresponds to an eye diagram value respectively, the analog front-end circuit of the receiver includes a plurality of sub-circuits, and the at least part of the look-up table includes The interface parameter values of each row in the row include multiple columns, and each column corresponds to each sub-circuit in the multiple sub-circuits; the target interface parameter value acquisition module is configured to obtain the target interface parameter value according to the multiple eye diagram values and the eye diagram. The thresholds identify target interface parameter values for the plurality of subcircuits.

In a third aspect, some embodiments of the present application provide a computer storage medium, and when the program is executed by a processor, the method described in the first aspect can be implemented.

In a fourth aspect, some embodiments of the present application provide an information processing device including a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the When the program is executed, the method described in the first aspect can be implemented.

Description of drawings

In order to explain the technical solutions of the embodiments of the present application more clearly, the following briefly introduces the accompanying drawings that need to be used in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application, therefore It should not be regarded as a limitation of the scope. For those of ordinary skill in the art, other related drawings can also be obtained from these drawings without any creative effort.

FIG. 1 is a partial structural block diagram of a receiver RX provided by an embodiment of the present application;

FIG. 2 is a flowchart of a method for searching receiver analog front-end circuit parameters provided by an embodiment of the present application;

3 is a schematic diagram of the composition of a receiver analog front-end circuit provided by an embodiment of the present application;

FIG. 4 is another flowchart of a method for searching receiver analog front-end circuit parameters provided by an embodiment of the present application;

5 is a schematic connection diagram of a receiver analog front-end circuit provided by an embodiment of the present application;

6 is a block diagram of the composition of an apparatus for searching for parameters of a receiver analog front-end circuit provided by an embodiment of the present application;

FIG. 7 is a schematic diagram of the composition of an information processing device provided by an embodiment of the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further definition and explanation in subsequent figures. Meanwhile, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

The following first lists the meanings of English abbreviations involved in some embodiments of the present application.

NRZ: Non-Return-to-Zero, non-return-to-zero coding, which is a general-purpose coding technique in high-speed serial communication interfaces.

ISI: Inter Symbol Interference, inter-symbol interference, which is a non-ideal factor in high-speed serial communication interfaces, will affect the quality of the eye diagram of the transmitting part.

LOS: Loss Of Signal, signal loss, it is a status indication signal defined in the high-speed serial communication interface.

ElecIdle: Electrical Idle, electrical idle, which is a status indication signal defined in the high-speed serial communication interface. RxElecIdle is electrical idle for the receiver.

RX Symbol: 1 byte received per parallel clock by the receiver defined in the high-speed serial communication interface.

PPM: Parts Per Million, which is the data frequency offset unit defined in the high-speed serial communication interface. PPMdrift is the frequency difference between the bit clock generated by the current clock recovery circuit and the high-speed differential data input at the receiving end, in units of one millionth.

FOM: Figure of Merit, figure of merit, which is a general technique for evaluating the quality of the eye diagram of the receiving part in high-speed serial communication interfaces.

SS-LMS: Sign-Sign Least Mean Square, symbol-symbol minimum mean square error, it is a general algorithm adopted by the decision feedback equalizer sub-circuit of the analog front end of the receiving part of the high-speed serial communication interface.

IP:Intellectual Property, intellectual property, it refers to a verified, reusable, integrated circuit module with a specific function, which can be divided into soft core, solid core and hard core according to the implementation type.

SOC: System-on-a-Chip, system-on-a-chip or system-on-chip, it is an integrated circuit with a special purpose, which contains a complete system and has all the contents of embedded software.

MAC: Medium Access Control, medium access control, it is the implementation of different protocol layers defined in the high-speed serial communication interface.

PMA: Physical Media Attachment Layer, physical medium layer, it is the physical layer defined in the high-speed serial communication interface, sometimes referred to as the PHY layer, and can be used as a SOC hard core IP.

PCS: Physical Coding Sublayer, physical coding sublayer, which is an intermediate layer defined in the high-speed serial communication interface between the MAC layer and the PHY layer.

PIPE: PHY Interface for PCI Express, SATA, USB3.1, Display Port, and Converged IO Architectures, a general-purpose PHY interface for PCIe/SATA/USB3.1/DisPlay port/Converged IO, which is a general-purpose PHY initiated by intel Interface bus protocol.

FFE: Feedback Forward Equalizer, the forward feedback equalizer of the transmission part in the high-speed serial communication interface, it is an integrated circuit with a dedicated target, including independent subsystems and corresponding software and hardware control interfaces, belonging to the transmission of PMA IP part of the function.

CDR: Clock Data Recovery, clock data recovery, it is an integrated circuit with a dedicated target, which includes independent subsystems and corresponding software and hardware control interfaces, which are part of the receiving function of PMA IP.

AFE: Analog Front-End, the analog front end of the receiving part in the high-speed serial communication interface, it is an integrated circuit with a dedicated target, including independent subsystems and corresponding software and hardware control interfaces, which are part of the receiving function of PMA IP .

ATT: Attenuator, the attenuator of the analog front end, it is an integrated circuit with a dedicated target, which is part of the AFE subsystem.

CTLE: Continuous Time Linear Equalizer, continuous time linear equalizer, it is an integrated circuit with a dedicated target, which includes an independent hardware control interface, which is part of the AFE subsystem.

VGA: Voltage Gain, voltage gain control circuit, it is an integrated circuit with a dedicated target, which includes an independent hardware control interface, which is part of the AFE subsystem.

DFE: Decision Feedback Equalizer, decision feedback equalizer, it is an integrated circuit with a dedicated target, including independent hardware control interface, which is part of the AFE subsystem.

The meanings of the English signal names involved in some embodiments of the present application are listed below.

rx_att_lvl[i-1:0]: The attenuation level control interface of the attenuator at the analog front end of the receiver. This interface has i bits to control 2i level attenuation.

rx_pole[l-1:0]: The pole value selection interface of the continuous-time linear equalizer in the analog front end of the receiver, this interface has l bits, and 2 ^l values can be selected.

rx_zero[jl-1:0]: Zero value selection interface of the continuous-time linear equalizer of the receiver analog front end, this interface has (jl) bits, and 2 ^(j -l) values can be selected.

rx_vga1[k-1:0]: The gain series control interface of the first stage gain control circuit of the analog front end of the receiver. This interface has k bits and controls the gain of 2 ^k stages.

rx_vga2[k-1:0]: The gain series control interface of the second stage gain control circuit of the analog front end of the receiver. This interface has k bits and controls the gain of 2 ^k stages.

rx_tap _m [n-1:0]: m tap coefficients of the decision feedback equalizer of the receiver analog front end, each coefficient corresponds to an n-bit binary value.

The technical problem to be solved by some embodiments of the present application is to provide a method for simultaneous searching and accelerated determination of parameters of at least two sub-circuits in a receiver analog front-end circuit RX AFE in a high-speed serial communication interface. It can be realized either by digital circuit or by software.

Compared with the related technical solutions, the embodiments of the present application use a look-up table including optional interface parameters of multiple sub-circuits, and simultaneously perform a joint search on the setting parameters of multiple sub-circuits corresponding to the analog front-end circuit of the receiving part, so as to solve the problem of multiple sub-circuits. The problem of mutual influence between the setting parameters improves the efficiency of determining the parameters of the analog front-end circuit.

Please refer to FIG. 1. FIG. 1 is a schematic structural diagram of a part of the receiver RX. The RX side of FIG. 1 includes a receiver analog front-end circuit 10 and a look-up table-based variable step search module 200 .

The receiver analog front end circuit 10 includes the following sub-circuits: an attenuator 110 , a continuous time linear equalizer 120 and a decision feedback equalizer 130 . It can be understood that the receiver analog front-end circuit may further include at least one stage of a voltage gain control circuit (not shown in FIG. 1 ).

The variable step size search module 200 based on the lookup table is configured to obtain the eye diagram values corresponding to the candidate interface parameter values of each row of the plurality of subcircuits based on the lookup table, and obtain the target interface parameter values of these subcircuits based on the eye diagram values. By loading these target interface parameter values, the sub-circuit can achieve a better compensation effect for the channel attenuation.

It should be noted that the look-up table includes at least three columns, wherein the first column includes the combined value between the multi-row channel attenuation value and the corresponding channel length (inch), and the remaining two columns correspond to the alternative interface parameter values of a sub-circuit respectively. , and the parameter value of the candidate interface in each row is related to the channel attenuation value of the row where it is located. For example, the first column of the lookup table is arranged according to the channel attenuation value from small to large, then the channel attenuation that can be compensated by the candidate interface parameters of each row in the lookup table needs to satisfy the principle of monotonically increasing; if the first column of the lookup table is If the channel attenuation values are arranged in descending order, the channel attenuation that can be compensated by the candidate interface parameters of each row in the lookup table needs to satisfy the monotonically decreasing principle. Some embodiments of the present application do not limit the at least two subcircuit types listed in the lookup table and the lookup table may include alternative interface parameters of three, four or even more subcircuits. For example, in some embodiments, the look-up table includes an alternate interface parameter column for the attenuation circuit and an alternate interface parameter column for a continuous-time linear equalizer; in other embodiments, the look-up table includes an alternate interface for the attenuation circuit. parameter list, an alternative interface parameter list of a continuous-time linear equalizer, and an alternative interface parameter list of a voltage gain control circuit; in other embodiments, the look-up table includes an alternative interface parameter list of an attenuation circuit, a continuous-time linear equalizer A list of alternative interface parameters for the voltage gain control circuit, and a list of alternative interface parameters for the criterion feedback equalizer.

A method for searching receiver analog front-end circuit parameters performed by the look-up table-based variable step size search module of FIG. 1 is exemplified below.

As shown in FIG. 2 , the method for searching for parameters of a receiver analog front-end circuit according to some embodiments of the present application includes: S101 , acquiring multiple eye diagram values corresponding to interface parameter values of at least some rows included in the lookup table, wherein, The interface parameter values of each row in the at least part of the rows correspond to an eye diagram value respectively, the analog front-end circuit of the receiver includes a plurality of sub-circuits, and the interface parameter values of each row of the look-up table include a plurality of columns, and each column is respectively associated with the Each sub-circuit in the plurality of sub-circuits corresponds to each other; S102, confirm the target interface parameter values of the plurality of sub-circuits according to the plurality of eye diagram values and the eye diagram threshold value.

In some embodiments of the present application, S101 may randomly select some rows from the look-up table to obtain the eye diagram value, and find the target interface parameters of each sub-circuit according to whether the maximum eye diagram value of these rows is greater than the eye diagram threshold value; In other embodiments of the present application, S101 obtains the eye diagram value corresponding to each row of interface parameters included in the lookup table, selects the maximum value from all the eye diagram values, and if the maximum eye diagram value is greater than the eye diagram threshold The interface parameter of the row corresponding to the eye diagram value is used as the target interface parameter value.

In some embodiments of the present application, S102 may simultaneously determine the target interface parameters of multiple sub-circuits including the criterion feedback equalizer according to the look-up table, and in other embodiments of the present application, the exclusion criterion is first confirmed according to the look-up table Feedback the target interface parameter values of the sub-circuits other than the equalizer, and then feed back the equalized target interface parameters according to the variable step size confirmation criterion based on the fixed target interface parameter values of these sub-circuits. It should be noted that when the analog front-end circuit of the receiver works with the target interface parameters, the compensation effect on the channel attenuation is better, which can improve the working performance of the receiver.

The method for searching the circuit parameters of the analog front end of the receiver according to the present application will be described below with reference to several specific examples.

In some embodiments of the present application, the look-up table includes an initial look-up table, and the initial look-up table is a table with a preset number of 2 ^r according to changes in channel lengths of different engineering applications, where r is greater than or A natural number equal to 1. S101 includes: obtaining 2 ^r eye diagram values corresponding to the analog front-end circuit according to the initial lookup table; S102 includes: searching for a maximum eye diagram value from the 2 ^r eye diagram values; confirming the maximum eye diagram value The image value is greater than or equal to the eye diagram threshold; the interface parameter value in the row corresponding to the maximum eye diagram value in the initial lookup table is used as the initial target interface parameter value; the eye diagram is searched according to the initial target interface parameter value and the local search A threshold determines at least part of the target interface parameter value, wherein the local search eye threshold is not less than the eye threshold. The local search eye diagram threshold is used to distinguish the eye diagram threshold defined in the rough search process, and the size of the local search eye diagram threshold should not be smaller than the eye diagram threshold in the rough and rough search process (that is, the process of determining the initial target interface parameter value). , in the specific implementation device, it is generally designed to be adjustable by software, and the default eye diagram threshold is the same as that in the rough search process. According to the local search eye diagram threshold, the search process corresponding to at least part of the target interface parameter values should be centered on the lookup table corresponding to the initial target interface parameter determined in the rough search process, and the search range should not exceed the adjacent lookup table. The difference between the upper and lower lines. As an example, the determining at least part of the target interface parameters according to the initial target interface parameter value and the local search eye diagram threshold value includes: determining multiple search ranges, wherein the number of the search ranges is the same as the number of the multiple search ranges. The number of sub-circuits is equal; traverse the multiple search ranges to obtain the maximum local eye diagram value; confirm that the maximum local eye diagram value is greater than the local search eye diagram threshold; The interface parameters are identified as the at least part of the target interface parameters.

In other embodiments of the present application, the look-up table includes an initial look-up table and an update look-up table, and the initial look-up table is a preset number of 2 ^r according to changes in channel lengths of different engineering applications . S101 includes: obtaining 2 ^r eye diagram values corresponding to the analog front-end circuit according to the initial lookup table; S102 includes: searching for a maximum eye diagram value from the 2 ^r eye diagram values; confirming the maximum eye diagram value The figure value is less than the eye diagram threshold; the initial target interface parameter value is determined according to the update lookup table and the eye diagram threshold, wherein the update lookup table is obtained by adding at least one row to the initial lookup table, And the channel attenuation that can be compensated by each row of interface parameters included in the update lookup table satisfies monotonicity; at least part of the target interface parameters are determined according to the initial target interface parameter value and the local search eye diagram threshold. As an example, the determining at least part of the target interface parameters according to the initial target interface parameter value and the local search eye diagram threshold value includes: determining multiple search ranges, wherein the number of the search ranges is the same as the number of the multiple search ranges. The number of sub-circuits is equal; traverse the multiple search ranges to obtain the maximum local eye diagram value; confirm that the maximum local eye diagram value is greater than the local search eye diagram threshold; The interface parameters are identified as the at least part of the target interface parameters.

It should be noted that the initial lookup table and the update lookup table involved in the above embodiments include columns corresponding to all subcircuits whose interface parameters need to be determined. In some embodiments, the sub-circuits in the receiver analog front-end circuit that need to determine the target interface parameters include the attenuator 110, the continuous-time linear equalizer 120 and the voltage gain control circuit, then the initial look-up table and the update look-up table respectively include The list of candidate interface parameters corresponding to the sub-circuits; in other embodiments, the sub-circuits in the receiver analog front-end circuit that need to determine the target interface parameters include the attenuator 110, the continuous-time linear equalizer 120 and the decision feedback equalizer 130, then The initial look-up table and the update look-up table respectively include candidate interface parameter columns corresponding to each sub-circuit.

Since the criterion feedback equalization DFE sub-circuit is mainly used to cancel the ISI (Inter Symbol Interference, inter-symbol interference) effect between high-speed data in high-speed serial communication, some embodiments of the present application provide an analog front-end circuit for searching receivers At the beginning of the parameter method, the circuit can be closed first, and the parameter values of the candidate interfaces corresponding to the column of criterion feedback equalization in the initial look-up table and the update look-up table are all set to zero. Correspondingly, in some embodiments of the present application, the target interface parameter includes a tap coefficient corresponding to a decision feedback equalizer, and the value of the column where the tap coefficient included in the look-up table is located is all zero; the same as the above implementation The difference is that, at this time, S102 includes: searching for part of the target interface parameter values according to the multiple eye diagram values and the eye diagram threshold value (that is, determining the rest of the parameters except the criterion feedback equalizer column by using the look-up table). The target interface parameter value of the column), wherein the partial target interface parameter value does not include the tap coefficient; according to the eye diagram threshold, the partial target interface parameter value and the step value search the tap coefficient, wherein, The step value is adjustable. For details of S101 included in these embodiments, reference may be made to the implementation manners of the foregoing embodiments, and details are not described herein.

In order to avoid the deadlock phenomenon caused by still being unable to obtain at least part of the target interface parameters from the lookup table after passing the maximum allowable number of cycles, in some embodiments of the present application, S102 may further include: confirming that after the maximum set number of cycles, the The multiple eye diagram values of , are all smaller than the eye diagram threshold; the target interface parameter value is determined according to an exhaustive method of variable step size.

It should be noted that, in order to improve the search speed, the step value and the variable step value in the above embodiment are multiples of 2. In order to save system resources and avoid invalid interface parameter value search, before executing S101, the method further includes: confirming that the receiver starts to receive data and the clock data recovery signal has locked the set application data rate. The above eye diagram threshold and eye diagram value are both indicators used to characterize the size of the eye diagram. For example, the eye diagram threshold or the type of the eye diagram value includes a figure of merit, a horizontal eye diagram edge indicator, or a vertical eye diagram edge indicator. For example, the eye diagram value and the eye diagram threshold may include the eye diagram width and the eye diagram height. When the eye diagram height reaches the set threshold (for example, the eye height threshold defined in the PCIE protocol is 30mV), the eye diagram width can be used as Search indicator; Similarly, when the eye diagram width reaches the set threshold (for example, the eye height threshold defined in the PCIE protocol is 0.35UI, and UI refers to the width of one chip), the eye diagram height width can also be used as the search indicator.

The receiver analog front-end circuit includes an attenuator 110, a continuous-time linear equalizer 120, a two-stage voltage gain control circuit (where each stage corresponds to a sub-circuit), and a decision feedback equalizer 130, and the decision feedback equalizer 130 is turned off first. Taking determining the target interface parameters of the remaining sub-circuits by using a look-up table as an example, the method for searching the circuit parameters of the analog front-end of the receiver according to some embodiments of the present application is exemplified.

As shown in FIG. 3 , the receiver analog front-end circuit includes five sub-circuits, which are an attenuator 110 (abbreviated as ATT), a continuous-time linear equalizer 120 (abbreviated as CTLE), and a two-stage voltage gain control, which are connected in sequence. Circuit VGA (only one stage is shown in the figure, where each stage corresponds to a sub-circuit) and decision feedback equalizer 130 . As an example, the attenuation level of the ATT circuit in FIG. 3 is 2 ⁱ levels, which are controlled by the i-bit interface signal rx_att_lvl[i-1:0], and each selected value of rx_att_lvl[i-1:0] corresponds to the receiving end The DC component of the input high-speed differential signal is attenuated by a certain dB value. By selecting different attenuation stages set by the circuit, the DC level of the input signal can be attenuated to within the set value (for example, 50mV), so that the analog front end of the receiver can be used for small signals. Processing; a series of curve groups implemented by the CTLE circuit has 2 ^j , each curve is represented by the pole rx_pole[l-1:0] represented by the l-bit interface signal and the zero point rx_zero[jl-1] represented by the (jl)-bit interface signal: 0] control, each selected value of rx_pole[l-1:0] corresponds to a receiver operating rate, and each selected value of rx_zero[jl-1:0] corresponds to the AC component of the high-speed differential signal input to the receiving end The attenuation is compensated for a certain dB value, so that the analog front end of the receiver can open the eye diagram; the VGA circuit has 2 stages, namely VGA1 and VGA2, and the voltage gain stage of each stage is 2 ^k , which are respectively determined by the k-bit interface signal rx_vga1[k-1: 0] and rx_vga2[k-1:0] control, each selected value of rx_vga1[k-1:0] and rx_vga2[k-1:0] mainly corresponds to the eye of the high-speed differential signal that will be output after being compensated by the CTLE circuit. High to increase a certain voltage value; the number of taps of DFE is m, each tap is controlled by an n-bit interface signal rx_tap _m [n-1:0], and m n-bit taps rx_tap _m [n-1:0] form an m Order transfer function used to compensate for ISI interference to the receiver.

Considering the attenuation series of the ATT circuit, the gain curve of the CTLE circuit, the change of the gain series of the VGA1 and VGA2 circuits and the control interface are monotonic. There is a proportional relationship between the size of the channel attenuation (dB) and the channel length (inch). Therefore, some embodiments of the present application preset a look-up table with a number of 2 ^r according to changes in channel lengths of different engineering applications, and the channel attenuation that can be compensated by the look-up table can be monotonically increasing. The alternative interface parameters of each subcircuit only need to compensate for a certain channel attenuation range, and do not necessarily require a strict linear relationship. For example, rx_pole[jl-1 in the preset ^2r lookup table: The 0] parameter is used to compensate the channel attenuation. With the increase of the interface value, the selected attenuation compensation stages increase monotonically, but there is no linear relationship between each compensation stage. The advantage of this setting is that it is not necessary to obtain the accurate attenuation of the current transmission channel in engineering applications, and the attenuation of the transmission channel is often easily affected by environmental changes such as temperature and voltage.

As an example, the values of the parameters related to the number of interface parameters corresponding to the five sub-circuits in FIG. 3 are: i=3, j=7, l=2, k=3, n=8, and the initial search The value of the parameter related to the size of the table is: r=3. The values of i, j, k, l, m and n are determined by the actual design circuit of the analog front end of the receiver. When these parameters are determined, the selection of r and r _max will ultimately affect the entire search algorithm in the middle. The running time is Tssm, as long as r and r _max are selected and Tssm is less than the maximum allowable search time defined by the system, the value of r is suitable. For example, referring to the lookup table defined in the PCIE protocol, there are 11 groups, and r generally selects 3 or 4 in an actual project. The initial look-up table that confirms the settings according to these parameters includes 8 rows, ie, 8 candidate interface parameter groups. The initial look-up table preset for the five sub-circuits of FIG. 3 is shown in Table 1.

Table 1 Initial Lookup Table

It should be noted that the five sub-circuits ATT, CTLE, VGA (including VGA1 and VGA2) and DFE circuits included in the receiver analog front-end circuit RX AFE in Figure 3 are only obtained according to the function and general structure. Realization, the naming of the control interface signals corresponding to each sub-circuit can be different from that in FIG. 3, and the number of signal lines included in each candidate interface parameter corresponding to each sub-circuit (for example, i=6, j=8, l=3, k=4, n=6) can also be different from the example corresponding to Table 1. According to different engineering applications, the value of each row of the candidate interface parameters set in the relevant initial lookup table corresponding to each sub-circuit may also be different from Table 1 (for example, the candidate interface parameters of the DFE sub-circuit corresponding to the length of each channel may not be Zero, tap ₀ [7:0] and tap ₁ [7:0] are the first and second order taps of the DFE sub-circuit, the compensation for the ISI effect is the most obvious, if it is known that the serial code stream currently received by the receiver is like "...1110111...0001000..." This kind of narrow pulse occurs frequently, you can set tap ₀ [7:0] and tap ₁ [7:0] to half of the value range, otherwise the initial value is still recommended to be 0); or ATT The optional interface parameter of each signal length corresponding to the subcircuit may not be 7. The attenuation level of the ATT subcircuit can be selected according to whether the actual engineering channel is Long/Short Line. If it is a Long Line, the attenuation level of the ATT subcircuit can be selected. It can be selected as the minimum attenuation level of 0. If it is Short Line, the attenuation level of the ATT sub-circuit can be selected as the maximum attenuation level of 7; or the CTLE sub-circuit corresponds to the alternative rx_pole[1:0] interface of each channel length. The parameter can be different from 0. rx_pole[1:0]=0 corresponds to the maximum working rate allowed by the receiver. The rx_pole[1:0] interface parameter can be selected according to the current actual working data rate, and the corresponding rx_zero[4:0] The interface parameters can be increased according to the actual channel attenuation; 1) The product value of interface parameters is not 40, the product value of (rx_vga1[2:0]+1) and (rx_vga2[2:0]+1) interface parameters is equivalent to the eye height and product value of the final output of the receiver analog front end The maximum value of the field 64 corresponds to the actual maximum eye height of the receiver analog front-end circuit. The product value of (rx_vga1[2:0]+1) and (rx_vga2[2:0]+1) interface parameters can be calculated according to the increasing and decreasing).

FIG. 4 provides how to quickly search for the target interface parameters that meet the requirements for the channel attenuation compensation effect for some sub-circuits (ie, ATT, CTLE, VGA1 and VGA2) of the multiple sub-circuits in FIG. 3 from multiple rows of candidate interface parameters. The method also provides how to find the tap coefficient of the DFE (that is, the target interface parameter of the DFE) that meets the requirements based on the determined target interface parameters of the ATT, CTLE, VGA1 and VGA2 subcircuits according to the set step size.

In step s1, all taps rx_tap _m [n-1:0] of the DFE circuit are set to 0, and the function of the DFE circuit is turned off. It can be understood that, in the initial lookup table of Table 1, the values of the candidate interface parameters in each row corresponding to the column of DFE are all zero.

Step s2, preset and store an initial look-up table with a number of 2 ^r (that is, the number of rows of the initial look-up table is 2 ^r ). In some embodiments, the channel attenuation that can be compensated by the initial lookup table is monotonically increasing and covers the maximum channel attenuation of the corresponding engineering application. For example, if the channel length and attenuation listed in the initial look-up table increase monotonically, the value of the candidate parameter in the column of the corresponding initial look-up table where the subcircuit for improving the channel high-frequency attenuation is located also increases monotonically. It should be noted that, assuming that the number of iterations from s4 to s2 is initially 1, if the jump is from s4, the initial lookup table is doubled (that is, the initial lookup table needs to be updated or the updated lookup table obtained in the last cycle needs to be updated), and The number of iterations from s4 to s2 is incremented by 1. For details on how to add the initial lookup table to obtain the updated lookup table, reference may be made to the description of the following step s4, which will not be repeated here in order to avoid repetition.

Step s3: After waiting for the RX receiver (or called the receiver) to start receiving data, and the clock data recovery CDR (Clock Data Recovery) signal included in the RX receiver has been locked to the current system application data rate, start the data rate based on the initial lookup table and The search process of updating the lookup table is to obtain target interface parameter values of at least part of the sub-circuits, specifically to this example, that is, to obtain target interface parameter values of ATT, CTLE, VGA1 and VGA2.

For example, it can be judged that the RX receiving end starts to have a high-speed differential signal input (that is, confirming the RX end by using the signal loss LOS (Loss Of Signal) and electrical idle Elec Idle (Electrical Idle) and other indication signals output by the signal detection circuit included in the RX receiving end of FIG. 3 . Start to receive data); According to the recovered clock returned by the RX receiver CDR and the input reference clock, the frequency difference of one millionth PPM (Parts Per Million) is less than the set value PPM _drift , or wait for a fixed duration Tmwait to potentially judge RX The receiver CDR has locked to the current data rate (ie, confirms that the clock data recovery signal has locked to the set application data rate).

Step s4: Traverse all 2 (r+r _max -1) preset look-up tables (including the initial look-up table and the update look-up table, and the size of the update look-up table is limited by the set maximum number of cycles r _max ), and find the largest among them. The eye diagram value and the target row in the lookup table corresponding to the maximum eye diagram value (that is, the row in which the target parameter value in the lookup table is located). It should be noted that, assuming that the initial preset 2 ^r lookup tables do not meet the eye diagram threshold, it is necessary to encrypt the lookup table (that is, to obtain the updated lookup table), and re-execute the search of S2->S3->S4. The cycle of the process The number of times is controlled by _rmax , e.g. the lookup table is increased by a factor of 1 each time it is looped. If the target row that satisfies the eye diagram threshold cannot be found after looping r _max times, it indicates that the rough search process fails, and skips directly to step S7; if the target row that meets the eye diagram threshold is found, it indicates that the rough search process is successful, After the process is completed, the initial target interface parameter value is obtained, and the step S5 is skipped to start the local fine search. That is, the steps according to the initial lookup table for the first time include: S2->S3->S4, and r _max =0.

Taking the eye figure of merit as an example of the type of eye threshold, s4 includes:

The effective value of the eye diagram figure of merit FOM (Figure of Merit, figure of merit) is preset to FOM _vld , so as to judge whether the corresponding eye diagram value obtained after loading the optional interface parameters on at least part of the sub-circuits meets the requirements of channel compensation, wherein , FOM _vld >0. After setting each set of parameters of the fixed RX AFE (that is, loading each sub-circuit with an alternative interface parameter value corresponding to a row in the look-up table), the duration of RX reception is Tmout.

行备选接口参数值，总共需要

次，记录RX每个查找表接收Tmout时间后对应的品质因数FOM值，找出其中最大FOM_max。如果FOM_max>FOM_vld，则最大FOM_max对应行的备选接口参数值记为LUP_max,把LUP_max对应的ATT电路初始目标接口参数记为rx_att_lvl_max(所述示例中用于表征粗略搜索过程中确定的这行查找表LUP_max中ATT接口参数rx_att_lv[2:0]＝rx_att_lvl_max)，CTLE电路初始目标接口参数记为rx_pole_max和rx_zero_max(所述示例中用于表征粗略搜索过程中确定的这行查找表LUP_max中CTLE接口参数rx_pole[1:0]＝rx_pole_max和rx_zero[4:0]＝rx_zero_max,)，VGA1和VGA2电路初始目标接口参数记为rx_vga1_max和rx_vga2_max(所述示例中用于表征粗略搜索过程中确定的这行查找表LUP_max中CTLE接口参数rx_vga1[2:0]＝rx_vga1_max和rx_vga2[2:0]＝rx_vga2_max,)，作为下一步做快速搜索的基点，得到这些初始目标接口参数值即确定了初始目标接口参数值；否则返回步骤s2，预设的查找表数目增加1倍(即更新初始查找表)，而在更新查找表中新增加的行可以位于：原有查找表相邻两行之间，或者位于原有查找表的第一行之前或者位于原有查找表最后一行之后，新增加的行的备选接口参数值可以由原有查找表相邻两行的备选接口参数值通过一定的加权方法计算得到。例如，新增加行的备选接口参数值是对原有查找表中相邻两行备选接口参数值的平均值，但是不只是局限于平均，可以是1/3，1/4或其它小于1的加权值。需要说明的是，在本申请的一些实施例中，每次更新后的查找表的行数与原有的查找表的行数相比增加一倍，但是本申请的实施例并不限定每次更新原有查找表所增加的具体行数。traverse

Line alternative interface parameter values, a total of

Next, record the corresponding quality factor FOM value after each lookup table of RX receives the Tmout time, and find the maximum FOM _max among them. If FOM _max > FOM _vld , the value of the candidate interface parameter of the row corresponding to the maximum FOM _max is denoted as LUP _max , and the initial target interface parameter of the ATT circuit corresponding to LUP _max is denoted as rx_att_lvl _max (in the example used to characterize the rough search process The ATT interface parameter _{rx_att_lv} [2:0]= _{rx_att_lvl max} in this row of lookup table LUP _max determined in The CTLE interface parameters rx_pole[1:0] = rx_pole _max and rx_zero[4:0] = rx_zero _max, ) in the lookup table LUP _max of this row, the initial target interface parameters of the VGA1 and VGA2 circuits are recorded as rx_vga1 _max and rx_vga2 _max (all In the above example, it is used to characterize the CTLE interface parameters rx_vga1[2:0]= _{rx_vga1max} and rx_vga2[2:0]=rx_vga2max _, ) in the lookup table LUP _max determined in the rough search process, as the next step to do a quick search If the initial target interface parameter value is obtained, the initial target interface parameter value is determined; otherwise, return to step s2, the preset number of lookup tables is doubled (that is, the initial lookup table is updated), and the newly added in the update lookup table The row can be located between two adjacent rows of the original lookup table, or before the first row of the original lookup table, or after the last row of the original lookup table. The candidate interface parameter values of the two adjacent rows of the lookup table are calculated by a certain weighting method. For example, the alternative interface parameter value of the newly added row is the average value of the alternative interface parameter values of the two adjacent rows in the original lookup table, but it is not limited to the average, it can be 1/3, 1/4 or other values less than A weighted value of 1. It should be noted that, in some embodiments of the present application, the number of rows in the lookup table after each update is doubled compared with the number of rows in the original lookup table, but the embodiments of the present application do not limit the number of rows in the lookup table each time. Update the specific number of rows added to the original lookup table.

The following table exemplarily describes the updated lookup table obtained after updating the initial lookup table, and exemplarily describes how to determine the alternative interface parameter value of the newly added row in the update lookup table.

As shown in Table 2, the five sub-circuit settings of the RX AFE corresponding to the newly added 8 preset look-up tables when i=3, j=7, l=2, k=3, n=8 and r=3 are given A list of alternative parameter values for .

Table 2 Update initial lookup table

It should be noted that the updated lookup table does not change the monotonicity of the original lookup table. For example, if the value of the alternative interface parameter used by the original lookup table to compensate for high frequency attenuation satisfies the monotonic increase, the update process is as follows: if the newly added row is the starting row of the lookup table, then the value of each column corresponding to the newly added row is The alternative interface parameter value is 1/2 of the original alternative interface parameter value of each column in the first row (this is just an example, in other examples, it can also be 1/3, etc.); if the new row is in the lookup table end line, then the alternative interface parameter of the new line is 3/2 of the value of the alternative interface parameter of the original last line (this is just an example, in other examples, it can also be 4/3, etc.); If the line is the middle line of two adjacent lines, the value of the candidate interface parameter of the new line is the average value of the two adjacent lines (this is just an example, in other examples, it can also be slightly larger than the average value, etc.), and the three In this case, the optional interface parameters of the new line cannot exceed the range of the corresponding interface signal.

Set the maximum number of iterations r _max , iterative steps s2, s3 and s4, when the number of iterations does not exceed r _max , if the FOM _max that meets the requirements is obtained, then for the current transmission channel, a set of RX AFE target interface parameters can be found. The internal receiving eye diagram of the RX is opened, and the fast search methods corresponding to some embodiments of the present application are convergent. Go to the next step s5 to perform a local search according to the local search threshold and the local search range, otherwise go to step s7 directly. The selection of the middle r and r _max will ultimately affect the entire running time Tssm of the middle search algorithm. As long as r and r _max are selected, Tssm is less than the maximum allowable search time defined by the system, then the r _max The selected value is appropriate.

It should be noted that, in some embodiments of high-speed serial communication, a serializer or deserializer Serdes (SERializer/DESerializer) EPHY or mobile industry processor interface MIPI (Mobile IndustryProcessor Interface) DPHY and other analog physical medium layer hardware are used. The core PMA IP is used to send and receive non-return-to-zero encoded NRZ data, and the analog PMA IP generally provides the eye size of the RX receiver (for example, by setting the FOM interface output eye size or internal storage registers to record the value of the eye size). In high-speed serial communication interfaces, if there is a situation where the analog PMA IP does not provide eye size FOM, then other metrics that can measure eye size can also replace the role of eye size figure of merit FOM, for example, horizontal/vertical Eye diagram Margin indicator, etc.

Step s5: With rx_att_lvl _max , rx_pole _max , rx_zero _max , rx_vga1 _max and rx_vga2 _max as the search base point (ie as the initial target interface parameter value), set the fast search range (ie the local search range) as ±delta, then with each sub-circuit The range of fast search for corresponding parameters is: (rx_att_lvl _max -delta, rx_att_lvl _max +delta), (rx_pole _max -delta, rx_pole _max +delta), (rx_zero _max -delta, rx_zero _max +delta), (rx_vga1 _max - delta, rx_vga1 _max +delta) and (rx_vga2 _max -delta, rx_vga2 _max +delta). It takes (2·delta+1) ⁵ times to traverse these fast search ranges in total, record the corresponding FOM value after each parameter receives the Tmout time, and find out the maximum FOM _max2 . There must be FOM _max2 > FOM _vld , then the ATT circuit parameters corresponding to the maximum FOM _max2 are recorded as rx_att_lvl _max2 , the CTLE circuit parameters are recorded as rx_pole _max2 and rx_zero _max2 , and the circuit parameters of VGA1 and VGA2 are recorded as rx_vga1 _max2 and rx_vga2 _max2 , that is, these are obtained. The target interface parameter value of the subcircuit. It should be noted that the local search eye pattern threshold in s5 is equal to the eye pattern threshold FOM _vld .

Step s6: Fix rx_att_lvl _max2 , rx_pole _max2 , rx_zero _max2 , rx_vga1 _max2 and rx_vga2 _max2 as the setting parameters of the ATT, CTLE, VGA1 and VGA2 circuits of the RX AFE (that is, as the target interface parameter value), first open the DFE circuit function to step Long λ iterates m n-bit taps rx_tap _m [n-1:0] in turn, a total of (m 2 ⁿ /λ) times are required, record the FOM value corresponding to each parameter after receiving the Tmout time, and find out Where the maximum FOM _max3 . There must be FOM _max3 > FOM _vld , then the DFE circuit parameter corresponding to the maximum FOM _max3 is recorded as rx_tapm_max3, that is, the target interface parameter value of the DFE is found.

So far, the fast search methods corresponding to some embodiments of the present application have ended, and the final search results (that is, the target interface parameter values) corresponding to the ATT, CTLE, VGA1, VGA2, and DFE subcircuit parameters of the RX AFE are in sequence: rx_att_lvlmax2, rx_polemax2, rx_zeromax2 , rx_vga1max2, rx_vga2max2 and rx_tapm_max3, the maximum eye FOM size obtained is FOMmax3.

In order to speed up the search speed and facilitate engineering implementation, the step value λ can be a multiple of 2.

The entire running duration of the fast search methods corresponding to some embodiments of the present application is:

where the minimum value is:

带入r＝3，delta＝2，m＝5，n＝8和λ＝1，有Tssm_min＝4413·Tmout。

Bringing in r=3, delta=2, m=5, n=8 and λ=1, there is Tssm _min =4413·Tmout.

Step s7: Turn on the DFE circuit function first, and set the ATT, CTLE, VGA1, VGA2 and DFE circuit parameters rx_att_lvl[i-1:0], rx_zero[l-1:0], rx_pole[j-l- of the RX AFE with a step size of λ2 1:0], rx_vga1[k-1:0], rx_vga2[k-1:0] and rx_tapm[n-1] are iterated in turn, and a total of (2(i+j+2k+m n)/λ2) is required Second, record the FOM value corresponding to each parameter after receiving the Tmout time, and find the maximum FOMmax4, then the ATT, CTLE, VGA1, VGA2 and DFE circuit parameters corresponding to the maximum FOMmax4 are recorded as: rx_att_lvlmax4, rx_polemax4, rx_zeromax4, rx_vga1max4, rx_vga2max4 and rx_tapm_max4, if FOMmax4>FOMvld, can also be used as the final search result corresponding to some embodiments of this application, and the obtained maximum eye diagram FOM size is FOMmax4; otherwise, a set of RX AFE setting parameters cannot be found after the current analog IP traversal is completed to make RX When the eye diagram of the internal receiving end is opened, the fast search methods corresponding to some embodiments of the present application can be ended, or the process can return to step s3 to restart the fast search methods corresponding to some embodiments of the present application.

In order to speed up the search speed and facilitate engineering implementation, the step size λ ₂ can be a multiple of 2.

In step s7, if multiple iterations of steps s2, s3 and s4 cannot be used to find a set of RX AFE setting parameters to open the eye diagram of the receiver inside the RX, the exhaustive method with variable step size can still be used to speed up the search speed. The overall running time of the variable-step exhaustive method is:

Bringing in i=3, j=7, k=3, m=5, n=8 and λ ₂ =1, there is Team =2 ⁵⁶ · _Tmout , which is much larger than Tssm _min .

Entering step s7 can be directly specified by the software without going through the iterations of steps s2, s3 and s4. For example, in an actual project, the user adopts a custom protocol for high-speed communication, and the training time of the link is not limited by any internationally known protocol, then the user can choose to directly enter step 7 of s7.

Step s8: When the system detects the hardware redo condition, or when the software is directly specified, it needs to return to step s1 to re-run the fast search method corresponding to the present invention.

In step s8, when it is detected that the RX end receiving data has a process of first stopping and then re-receiving, or the RX receiving end CDR locks and then has a process of getting out of lock, or it is potentially speculated that the RX receiving end CDR has a process of getting out of lock, such as RX receiving Data errors lead to 10b/8b decoding errors, RX Symbol loss of lock leads to boundary movement, the current high-speed serial communication link is disconnected, etc., all of which can be regarded as hardware redo conditions detected by the system.

The MAC (Medium Access Control, media access control) layers of various high-speed serial protocols and the PMA simulation IP are connected through the physical coding sublayer PCS (Physical Coding Sublayer) layer. When some embodiments of the present application are implemented in practical projects, The flowchart shown in Figure 2 can be realized by using a hardware digital circuit without adding additional PCS PIPE (PHY Interface for PCI Express, SATA, USB3.1, Display Port, and Converged IOArchitectures, PCIe/SATA/USB3.1/DisPlay port/ Generic PHY interface for Converged IO) signals.

When the PIPE signal Reset# in the PCS of the standard physical coding sublayer is released, the technical solutions provided by some embodiments of the present application are started, for example, step s1 is entered, and step s2 is executed in sequence; when the electrical idle indication RxElecIdle of the PIPE signal receiver is pulled low, enter Step s3, after waiting for a set time Tmwait, jump to step s4, execute steps s5 and s6 in turn, and then enter step s8; when the PIPE signal RxElecIdle jumps from low to high, or the receiver in the PCS receives a word for each parallel clock. When the RX Symbol lock indication signal RxValid jumps from high to low, or the error indication RxStatus[2:0]=4/7 given by the 10b/8b decoding function module in the PCS, it means that the current system detects a hardware redo condition , skip directly to step s1, and re-execute the flow chart shown in FIG. 2; enter step s1 to redo and enter step s7, which can be directly specified by software.

If the various setting parameters of RX AFE, RX internal receiving eye diagram size FOM, the LOS/RxElecidle indication returned by the RX receiving end, the PPM _drift returned by RX CDR, and the RxValid/RxStatus indication inside PCS can be controlled/accessed through the register interface, then this When some embodiments of the application are implemented in an actual project, pure software can also be used to implement the method shown in FIG. 2 .

As shown in FIG. 5 , FIG. 5 includes a variable step size search module 100 based on a lookup table for performing the method in FIG. 2 or part of the steps in FIG. [l-1:0], rx_zero[jl-1:0], rx_vga1[k-1:0], rx_vga2[k-1:0] and rx_tap _m [n-1:0] are sent directly through the connection line Physical medium layer PMA. After the variable step size search module 100 based on the look-up table in FIG. 5 exits RESET#, after receiving the LOS/RxElecIdle indication transmitted by the PMA through the connecting line as low, it is clear that the current receiver analog front end already has a high-speed differential signal input , the variable step size search module 100 based on the lookup table continues to wait, and when the RxValid signal is received high, the search module 100 knows that the CDR of the current PMA has been locked (when there is no RxValid signal, the PPMdrift value can be less than the set value through the to potentially determine that the current CDR is locked), thereby starting the method in Figure 2 or some of the steps in Figure 4 to jointly search for the target interface parameters of multiple sub-circuits, and at the same time receive the FOM value transmitted by the PMA as an indicator of eye diagram quality. When the variable step size search module 100 based on the lookup table starts from s1, goes through multiple iterations of s2, s3 and s4, and finally goes through s5 and s6 to s8; or the variable step size search module 100 based on the lookup table starts from s1, After multiple iterations of s2, s3 and s4, and finally through s7 to s8; or the variable step size search module 100 based on the lookup table starts from s7 and finally reaches s8, after these three modes complete the search, the variable step size based on the lookup table The step search module 100 will find the target interface signals rx_att_lvl[i-1:0], rx_pole[l-1:0], rx_zero[jl-1:0], rx_vga1[k-1:0], rx_vga2[ k-1:0] and rx_tap _m [n-1:0] are directly sent to the PMA through the connection line. After completing the search, the variable step size search module 100 based on the lookup table will stop at s8, when the RXSymbol lock indication signal RxValid jumps from high to low, or the error indication RxStatus[ When 2:0]=4/7, it means that the current system detects the hardware redo condition, and directly jumps to step s1 to start a new round of search.

Please refer to FIG. 6. FIG. 6 shows an apparatus for searching analog front-end circuit parameters of a receiver provided by an embodiment of the present application. It should be understood that the apparatus corresponds to the method embodiment of FIG. For each step, the specific function of the device can be referred to the above description, and to avoid repetition, the detailed description is appropriately omitted here. The device includes at least one software function module that can be stored in the memory or solidified in the operating system of the device in the form of software or firmware, and the device for searching the analog front-end circuit parameters of the receiver includes: an eye diagram value acquisition module 101 is configured to obtain multiple eye diagram values corresponding to interface parameter values of at least some rows included in the look-up table, wherein each row in the at least some rows corresponds to an eye diagram value respectively, and the analog front-end circuit of the receiver includes a plurality of sub-circuits, the interface parameter values of each row in the at least part of the rows included in the look-up table include a plurality of columns, and each column corresponds to each sub-circuit in the plurality of sub-circuits; the target interface parameter value acquisition module 102 , configured to confirm target interface parameter values of the plurality of sub-circuits according to the plurality of eye diagram values and eye diagram thresholds.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, for the specific working process of the device described above, reference may be made to the corresponding process in the method in FIG. 2 , which will not be repeated here.

Some embodiments of the present application provide a computer storage medium, and when the program is executed by a processor, the method described in FIG. 2 can be implemented.

As shown in FIG. 7 , some embodiments of the present application provide an information processing device 500, including a memory 510, a processor 520, and a computer program stored on the memory 510 and executable on the processor 520, wherein , when the processor 520 reads a program from the memory 510 through the bus 530 and executes the program, the method described in FIG. 2 can be implemented.

The processor 520 may process digital signals and may include various computational structures. For example, a complex instruction set computer architecture, a structured reduced instruction set computer architecture, or an architecture that implements a combination of multiple instruction sets. In some examples, processor 520 may be a microprocessor.

Memory 510 may be used to store instructions executed by processor 520 or data related to the execution of instructions. These instructions and/or data may include codes for implementing some or all functions of one or more modules described in the embodiments of the present application. The processor 520 of the embodiment of the present disclosure may be used to execute the instructions in the memory 510 to implement the method shown in FIG. 2 . Memory 510 includes dynamic random access memory, static random access memory, flash memory, optical memory, or other memories known to those skilled in the art.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may also be implemented in other manners. The apparatus embodiments described above are merely illustrative, for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architectures, functions and possible implementations of apparatuses, methods and computer program products according to various embodiments of the present application. operate. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code that contains one or more functions for implementing the specified logical function(s) executable instructions. It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It is also noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented in dedicated hardware-based systems that perform the specified functions or actions , or can be implemented in a combination of dedicated hardware and computer instructions.

In addition, each functional module in each embodiment of the present application may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, Read-Only Memory (ROM, Read-Only Memory), Random Access Memory (RAM, Random Access Memory), magnetic disk or optical disk and other media that can store program codes .

The above descriptions are merely examples of the present application, and are not intended to limit the protection scope of the present application. For those skilled in the art, various modifications and changes may be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the protection scope of this application. It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited to this. should be covered within the scope of protection of this application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

Claims (15)

1. A method for searching parameters of an analog front-end circuit of a receiver, the method comprising:

the method comprises the steps of obtaining a plurality of eye pattern values corresponding to interface parameter values of at least part of rows included by a lookup table, wherein the interface parameter values of each row in the at least part of rows respectively correspond to one eye pattern value, an analog front end circuit of a receiver comprises a plurality of sub-circuits, the interface parameter values of each row of the lookup table include a plurality of columns, each column of the interface parameter values respectively corresponds to each sub-circuit in the plurality of sub-circuits, and the plurality of sub-circuits comprise: the system comprises an attenuator, a continuous time linear equalizer and a decision feedback equalizer, wherein parameters of the decision feedback equalizer comprise tap coefficients;

identifying target interface parameter values for the plurality of sub-circuits based on the plurality of eye pattern values and eye pattern thresholds;

wherein said validating target interface parameter values for the plurality of sub-circuits as a function of the plurality of eye values and eye threshold values comprises:

searching for a portion of the target interface parameter values based on the plurality of eye values and the eye threshold, wherein the portion of the target interface parameter values does not include the tap coefficients;

searching the tap coefficients according to the eye threshold, the partial target interface parameter value and a step value, wherein the step value is adjustable.

2. The method of claim 1, wherein the lookup table comprises an initial lookup table, and the initial lookup table is a preset number of rows of 2 according to a change in channel length for different engineering applications^rR is a natural number greater than or equal to 1;

the obtaining of the plurality of eye pattern values corresponding to the interface parameter values of at least part of the rows included in the lookup table includes:

obtaining 2 corresponding to the analog front-end circuit according to the initial lookup table^r-each of said eye values;

the validating target interface parameter values for the plurality of sub-circuits as a function of the plurality of eye values and eye threshold values comprises:

from said 2^rSearching the maximum eye pattern value in the eye pattern values;

confirming that the maximum eye value is greater than or equal to the eye threshold;

taking the interface parameter value of the row corresponding to the maximum eye diagram value in the initial lookup table as an initial target interface parameter value;

determining at least a portion of the target interface parameter values based on the initial target interface parameter values and a local search eye threshold, wherein the local search eye threshold is not less than the eye threshold.

3. The method of claim 1, wherein the lookup table comprises an initial lookup table and an updated lookup table, and the initial lookup table is preset to have a number of 2 according to the channel length variation of different engineering applications^rTable (2);

the obtaining of the plurality of eye pattern values corresponding to the interface parameter values of at least part of the rows included in the lookup table includes:

obtaining 2 corresponding to the analog front-end circuit according to the initial lookup table^r-each of said eye values;

the validating target interface parameter values for the plurality of sub-circuits as a function of the plurality of eye values and eye threshold values comprises:

from said 2^rSearching the maximum eye pattern value in the eye pattern values;

confirming that the maximum eye value is less than the eye threshold;

determining an initial target interface parameter value according to the updated lookup table and the eye pattern threshold, wherein the updated lookup table is obtained by adding at least one row in the initial lookup table, and channel attenuation which can be compensated by each row of interface parameters in the updated lookup table meets monotonicity;

determining at least a portion of the target interface parameters based on the initial target interface parameter values and a local search eye threshold.

4. The method of claim 2 or 3, wherein said determining at least a portion of said target interface parameters based on said initial target interface parameter value and a local search eye threshold value comprises:

determining a plurality of search ranges, wherein the number of the search ranges is equal to the number of the plurality of sub-circuits;

traversing the plurality of search ranges to obtain a maximum local eye diagram value;

confirming that the maximum local eye value is greater than the local search eye threshold;

and confirming the interface parameter corresponding to the maximum local eye diagram value as the at least part of target interface parameter.

5. A method according to claim 2 or 3, wherein the channel attenuation which can be compensated for by each row of interface parameters contained in the initial look-up table is monotonic.

6. The method of claim 1, wherein the step value is a multiple of 2.

7. The method of claim 1,

the validating target interface parameter values for the plurality of sub-circuits as a function of the plurality of eye values and eye threshold values comprises:

confirming that the eye pattern values obtained after the maximum set number of cycles are smaller than the eye pattern threshold value;

and determining the target interface parameter value according to an exhaustive method of variable step length.

8. The method of claim 7, wherein the variable step size is a multiple of 2.

9. The method of any of claims 1-3, 6-8, wherein the plurality of sub-circuits comprises: at least two of attenuator ATT, continuous time linear equalizer CTLE, voltage gain control circuit VGA and criterion feedback equalization.

10. The method of claim 1, wherein before obtaining the plurality of eye values corresponding to the interface parameter values of at least some of the rows included in the lookup table, the method further comprises: the receiver is confirmed to start receiving data and the clock data recovery signal has locked to the set application data rate.

11. The method of claim 1, wherein the eye threshold and the eye value are both indicators for characterizing eye size.

12. The method of claim 11, wherein the eye threshold or the type of the eye value comprises a figure of merit, a lateral eye edge indicator, or a longitudinal eye edge indicator.

13. An apparatus for searching parameters of an analog front end circuit of a receiver, the apparatus comprising:

an eye pattern value obtaining module, configured to obtain a plurality of eye pattern values corresponding to interface parameter values of at least part of rows included in a lookup table, where each of the interface parameter values in the at least part of rows corresponds to one eye pattern value, an analog front end circuit of the receiver includes a plurality of sub-circuits, each of the interface parameter values in the lookup table includes a plurality of columns, and each of the columns corresponds to one of the sub-circuits, respectively, and the plurality of sub-circuits include: the system comprises an attenuator, a continuous time linear equalizer and a decision feedback equalizer, wherein parameters of the decision feedback equalizer comprise tap coefficients;

a target interface parameter value acquisition module configured to confirm a target interface parameter value for the plurality of sub-circuits according to the plurality of eye pattern values and an eye pattern threshold;

wherein,

the target interface parameter value acquisition module is configured to:

searching for a portion of the target interface parameter values based on the plurality of eye values and the eye threshold, wherein the portion of the target interface parameter values does not include the tap coefficients;

searching the tap coefficients according to the eye threshold, the partial target interface parameter value and a step value, wherein the step value is adjustable.

14. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, is adapted to carry out the method of any one of claims 1 to 11.

15. An information processing apparatus comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor when executing the computer program is operable to implement the method of any one of claims 1 to 11.

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