CN115065572B - CAN FD controller for vehicle-mounted electronic system - Google Patents

Abstract

The invention discloses a CAN FD controller for vehicle-mounted electronic systems, which includes: a memory register used to store received and sent data to obtain bit data; an interrupt manager used to monitor the status of CANFD IP and Send interrupt information when a preset situation occurs; bus sampler, used to receive and send data; TXT buffer, used to access bit data from the memory register, insert the frame data into its own buffer, and store the single frame data Transmitted to the TX arbiter in the internal RAM; the TX arbiter is used to determine the target TXT buffer and send the frame data in the target TXT buffer to the CAN protocol core module; the CAN protocol core module is used to process the frame data Perform parallel-to-serial conversion and send the resulting serial data to the bus sampler so that the bus sampler sends serial data. The above-mentioned CAN FD controller separates the data sending process and the data receiving process to avoid mutual influence between the two.

Description

A CAN FD controller for vehicle electronic systems

Technical field

The invention belongs to the field of CAN bus technology, and specifically relates to a CAN FD controller for vehicle-mounted electronic systems.

Background technique

At present, the CAN bus is widely used in commercial vehicles, but the introduction of serial communication has led to an increasing demand for CAN communication bandwidth. The data segment of the CAN FD (CAN with Flexible Data rate) bus has a higher transmission rate, so CAN FD is used The bus is gradually becoming a trend.

As the core component of CAN FD bus communication, the CAN FD controller has a variety of implementation structures and methods. In related technologies, the CAN FD controller integrates the data sending and receiving processes in the same functional module. This design method makes the process of processing information prone to errors and is too complex when analyzing the controller, which is not conducive to improving the processing speed.

Contents of the invention

In order to solve the above-mentioned problems existing in the prior art, the present invention provides a CAN FD controller for vehicle-mounted electronic systems. The technical problems to be solved by the present invention are achieved through the following technical solutions:

The invention provides a CAN FD controller for vehicle-mounted electronic systems, including: AHB interface conversion module, memory register, interrupt manager, bus sampler, RX buffer, multiple TXT buffers, TX arbiter and CAN protocol core module; among them,

The AHB interface conversion module is used to read and write memory registers, RX buffers and TXT buffers;

The memory register is used to store received and sent data to obtain bit data;

The interrupt manager is used to monitor the status of the CAN FD IP and send interrupt information when a preset situation occurs;

The bus sampler is used to receive data and send data;

The TXT buffer is used to access bit data from the memory register through the memory bus of the CAN FD controller, and after inserting the frame data into its own buffer, store the single frame data in the internal RAM and transmit it to the TX arbitration device;

The TX arbiter is used to determine a target TXT buffer from the plurality of TXT buffers, and send the frame data in the target TXT buffer to the CAN protocol core module;

The CAN protocol core module is used to perform parallel-to-serial conversion on the received frame data, and send the obtained serial data to the bus sampler, so that the bus sampler sends the serial data.

In one embodiment of the invention, a frame filter is further included;

The CAN protocol core module is also used to perform serial-to-parallel conversion on the frame data, and send the obtained parallel data to the frame filter.

In one embodiment of the present invention, the frame filter is used to filter the valid data of the RX buffer according to the CAN identifier in the received parallel data, and send the valid data to the RX buffer;

The RX buffer is used to store the valid data.

In one embodiment of the invention, a prescaler is also included;

The prescaler is used to generate timing information required for CAN FD protocol transmission, and send the timing information to the AHB interface conversion module, the memory register, the interrupt manager, and the bus sampling , the plurality of TXT buffers, the TX arbiter, the CAN protocol core module, the frame filter and the RX buffer.

In one embodiment of the present invention, the TX arbiter is specifically used to determine the target TXT based on the current status and preset priority of each TXT buffer, as well as the type and identifier size of the frame data in each TXT buffer. buffer, and sends the frame data in the target TXT buffer to the CAN protocol core module.

In one embodiment of the present invention, the interrupt manager is specifically used to monitor the status of the CAN FD IP and send interrupts to the on-chip system or memory register where the CAN FD controller is located when a preset situation occurs. information.

In one embodiment of the present invention, the bus sampler is also used to detect the transmission delay time of received data and transmitted data, and to detect whether there are bit errors in the received data and transmitted data.

Compared with the prior art, the beneficial effects of the present invention are:

The invention provides a CAN FD controller for vehicle-mounted electronic systems, including: AHB interface conversion module, memory register, interrupt manager, bus sampler, RX buffer, multiple TXT buffers, TX arbiter and CAN protocol core module, because the CAN FD controller separates the data sending process and the data receiving process to avoid the mutual influence between the two; at the same time, the CAN FD controller provided by the present invention redivides the functions of each module and can optimize the work according to the requirements of the protocol specification. process.

The present invention will be further described in detail below with reference to the accompanying drawings and examples.

Description of the drawings

Figure 1 is a schematic structural diagram of a CAN FD controller for vehicle-mounted electronic systems provided by an embodiment of the present invention;

Figure 2 is a schematic diagram of the operation of the RX buffer in the CAN FD controller for vehicle-mounted electronic systems provided by the embodiment of the present invention;

Figure 3 is a schematic diagram of the operation of the TX arbiter in the CAN FD controller for vehicle-mounted electronic systems provided by the embodiment of the present invention;

Figure 4 is a schematic diagram of the operation of the TXT buffer in the CAN FD controller for vehicle-mounted electronic systems provided by the embodiment of the present invention.

Detailed ways

The present invention will be described in further detail below with reference to specific examples, but the implementation of the present invention is not limited thereto.

Figure 1 is a schematic structural diagram of a CAN FD controller for vehicle-mounted electronic systems provided by an embodiment of the present invention. Referring to Figure 1, an embodiment of the present invention provides a CAN FD controller for vehicle-mounted electronic systems, including: AHB interface conversion module, memory register, interrupt manager, bus sampler, RX buffer, multiple TXT buffers, TX arbiter and CAN protocol core module; among them,

AHB interface conversion module, used to read and write memory registers, RX buffers and TXT buffers;

Memory register, used to store received and sent data to obtain bit data;

Interrupt manager, used to monitor the status of CAN FD IP and send interrupt information when preset situations occur;

Bus sampler, used to receive data and send data;

The TXT buffer is used to access bit data from the memory register through the memory bus of the CAN FD controller, insert the frame data into its own buffer, and then store the single frame data in the internal RAM and transmit it to the TX arbiter;

TX arbiter, used to determine the target TXT buffer from multiple TXT buffers and send the frame data in the target TXT buffer to the CAN protocol core module;

The CAN protocol core module is used to perform parallel-to-serial conversion on the received frame data, and send the obtained serial data to the bus sampler, so that the bus sampler sends serial data.

As shown in Figure 1, the CAN FD controller provided by the present invention includes: AHB interface conversion module, memory register, interrupt manager, bus sampler, multiple TXT buffers, TX arbiter and CAN protocol core module. Specifically, in the above-mentioned CAN FD controller, the AHB interface conversion module (AHB Interface) is compatible with the AMBA 2.0AHB interface specification and is used to read and write memory registers, RX buffers and TXT buffers; memory registers ) contains all registers in CANFD and is used to store received and sent data. The obtained bit data represents the status of CAN FD; the interrupt manager (Interrupt manager) is used to monitor the status of CAN FD IP and respond in advance. Send interrupt information when the situation occurs; the Bus Sampler is used to send and receive data; the TXT buffers are used to access bit data from the memory register through the memory bus of the CAN FD controller and the SW command, and After inserting the frame data into its own buffer, the single frame data is stored in the internal RAM and transmitted to the TX arbitrator (TX arbitrator). It should be understood that the bit data obtained by the TXT buffer from the memory register includes the work of the CAN FD controller mode, software commands and frame data written to the corresponding TXT buffer, that is to say, the obtained bit data includes the information required for the operation of the TXT buffer and the frame data stored in RAM; further, the TX arbiter is used from Determine the target TXT buffer among multiple TXT buffers, and send the frame data in the target TXT buffer to the CAN protocol core module; the CAN protocol core module is used to perform parallel-to-serial conversion on the received frame data, and Send the obtained serial data to the bus sampler so that the bus sampler sends serial data.

Optionally, the CAN FD controller also includes a frame filter;

The CAN protocol core module is also used to perform serial-to-parallel conversion of frame data and send the resulting parallel data to the frame filter.

In this embodiment, the CAN protocol core module may include protocol control, bit stuffing, bit destuffing, fault confinement, CAN CRC checksum operation control module. Exemplarily, the above-mentioned CAN FD controller also includes frame filters; during the process of sending data, the CAN protocol core module is also used to perform serial-to-parallel conversion of the frame data, and send the obtained parallel data to Frame filter.

Further, the frame filter is used to filter the valid data of the RX buffer according to the CAN identifier in the received parallel data, and send the valid data to the RX buffer;

RX buffer, used to store valid data.

Specifically, the CAN FD controller also includes an RX buffer. After the frame filter receives the parallel data, it can filter out the valid data to the RX buffer based on the CAN identifier contained in the parallel data, and save the valid data to the RX buffer. Data is sent to the RX buffer.

Illustratively, the frame filter identifier type and frame type are controlled by "driving bus". Frame filters apply to 11-bit and 29-bit identifiers and consist of filters A, B, C and Range. If the input identifier matches at least one, it is considered valid data; frame types include: CAN Basic, CAN Extended, CAN FD Basic and CAN FD Extended. The frame type can be selectively filtered, and the frame filter can choose not to perform comprehensive processing. , can also be disabled at runtime. Of course, if the frame filter is disabled, no frame data will be filtered out.

Figure 2 is a schematic diagram of the operation of the RX buffer in the CAN FD controller for vehicle-mounted electronic systems provided by the embodiment of the present invention. As shown in Figure 2, the RX CAN frame during data reception is stored in the RX buffer RAM and is controlled by the protocol control FSM. The RX frame is read word by word from the frame filter, the RX buffer stores the data continuously as it is received, and at the end it is committed to memory for use by the processor. If an "overflow" or "release of the receive buffer" occurs at the same time, the frame data is restored.

Optionally, the CAN FD controller also includes a prescaler;

Prescaler, used to generate the timing information required for CAN FD protocol transmission, and send the timing information to the AHB interface conversion module, memory register, interrupt manager, bus sampler, multiple TXT buffers, TX arbiter, CAN protocol core module, frame filter and RX buffer.

In this embodiment, the CAN FD controller also includes a prescaler. The prescaler can generate the timing information required for CAN FD protocol transmission based on the relevant information configured in the previous stage, and send the timing information to the AHB interface respectively. Conversion module, memory register, interrupt manager, bus sampler, multiple TXT buffers, TX arbiter, CAN protocol core module, frame filter and RX buffer to control the work of the entire CAN bus network. Optionally, the prescaler includes transmission rate count, transmission bit segment count, resynchronization and hard synchronization execution, TX and RX trigger timing and readback mechanism. It should be noted that the nominal timing and data timing adopt different counting system.

Figure 3 is a schematic diagram of the operation of the TX arbiter in the CAN FD controller for vehicle-mounted electronic systems provided by the embodiment of the present invention. As shown in Figure 3, the initial state of the TX arbiter is arbitration idle, and then the upper and lower limits of the timestamp are obtained for subsequent frame data transmission, that is, from the TX arbiter module to the protocol core module. Next, the TX arbiter The frame data type in the TXT buffer is judged, and the identifier information in each frame data is obtained and then arbitrated. After the arbitration is completed, the successfully arbitrated frame data is transmitted to the protocol kernel module, and the transmission is locked until the transmission is completed, and then returns to arbitration. idle phase.

Optionally, the TX arbiter is specifically used to determine the target TXT buffer according to the current status and preset priority of each TXT buffer, as well as the type and identifier size of the frame data in each TXT buffer, and assign the target TXT buffer to The frame data in the controller is sent to the CAN protocol core module.

Specifically, please refer to Figure 3. The TXT arbiter first obtains the timestamp of the frame data in each TXT buffer, and then judges the type and identifier of the frame data in each TXT buffer, so as to determine the type and identifier of the frame data in each TXT buffer. The priority and current status, as well as the type of frame data and the size of the identifier are used to obtain the arbitration result, that is, the target TXT buffer is determined from multiple TXT buffers. Further, the timestamp of the frame data in the target TXT buffer is compared with the external timestamp. Only when the timestamp is lower than the value of the external timestamp, the corresponding frame data is marked as valid for the CAN Core, and then the This frame data is loaded into the output of the TX arbiter.

Figure 4 is a schematic diagram of the operation of the TXT buffer in the CAN FD controller for vehicle-mounted electronic systems provided by the embodiment of the present invention. Please refer to Figure 4. When the CAN FD controller is in the off state, the TXT buffer enters the "transmission failure" state, and the TXT buffer will generate an interrupt when it transitions to the "transmission complete", "abort", or "transmission failure" state. . When the TXT buffer is in the "ready" state, the TX arbiter can select the target TXT buffer from multiple TXT buffers. When the TXT buffer is in the "ready", "transmitting", and "transmission terminated" states, the TX arbiter can read the data in the TXT buffer; when the TXT buffer is in the "empty", "transmission completed", "aborted" state ", "Transmission failed" status, the data can be written to the corresponding address storage space. When the TXT buffer is in the "empty", "transmission completed", "aborted", "transmission failed" state and the "set ready" command issued from the memory register is valid, it transitions to the "ready" state; when the TXT buffer is in the When the "Transfer Complete", "Abort", "Transfer Failed" state and the "Set to Empty" command issued from the memory register is valid, it transitions to the "Empty" state; when the TXT buffer is in the "Ready" state and the "Set to Empty" command from the memory register is valid When the "Set Abort" command issued by the module is valid, it switches to the "Abort" state; when the TXT buffer is in the "Ready" state and the transmission start signal is valid (starts transmitting frame data to the TX arbiter), it switches to the "In Progress" state. Transmitting" state; when the TXT buffer is in the "Transmitting" state but its transmission is unsuccessful, the transition returns to the "Ready" state; when the TXT buffer is in the "Transmitting" state and the "Set Abort" command is caused by the occurrence of an abnormal state When valid, it transitions to the "transmission terminated" state, so that the transmission is unsuccessful and enters the "aborted" state; when the TXT buffer is in the "transmitting" state and the transmission is successful, it transitions to the "transmission completed" state; when the TXT buffer is in the "transmitting" state When the "transmission terminated" state is reached and the retransmission limit is reached or the bus is closed, it transitions to the "transmission failed" state.

Optionally, the interrupt manager is specifically used to monitor the status of the CAN FD IP and send interrupt information to the on-chip system or memory register where the CAN FD controller is located when a preset situation occurs.

In this embodiment, the interrupt manager mainly monitors the status in the CAN FD IP and sends interrupt information to the external or memory register when a preset situation occurs. At the same time, the interrupt manager module can also use the input port drv_bus[1023:0] To control the enabling and masking of each interrupt.

It should be noted that the preset conditions in this embodiment refer to arbitration loss, bit rate conversion, error occurrence, error warning limit reached, fault limit status changed, received frame data valid, sent frame data valid, RX buffer data overflow and RX buffer empty/full etc.

Optionally, the bus sampler is also used to detect the transmission delay time of received data and transmitted data, and to detect whether there are bit errors in the received data and transmitted data.

Specifically, the bus sampler detects the transmission delay time of received or transmitted data in a "readback" manner, and whether there are bit errors during the transmission and reception processes. If there is a transmission time delay, it can be detected by subsampling the offset. Eliminate send time delays.

In summary, in the CAN FD controller provided by the present invention, the controller area network (CAN FD) IP is used to realize the serial reception and transmission of data in its CAN FD network; when sending data, the CAN FD IP will be sent For parallel-to-serial conversion of data, you can add a data start flag bit to the serial data, add a CRC check (Cyclic Redundancy Check, cyclic redundancy check) bit and several data control bits after the serial data; when receiving data, CAN FD IP filters, analyzes and caches the received data read serially, and at the same time checks the correctness of data reception through the CRC check mechanism. CANFD IP is connected to AMBA AHB through AMBA 2.0AHB interface. Through this interface, the internal controller can read or write CAN FD internal registers, set CAN FD or read CAN FD status. In addition, the CAN FD IP also provides an interrupt interface. In CAN FD IP, the transmission baud rate, working mode, parity check, etc. of the IP can be set through register settings. Optionally, the CAN FD controller is integrated in the SOC (System on chip) to realize serial reception and transmission of data.

It can be seen from the above embodiments that the beneficial effects of the present invention are:

The invention provides a CAN FD controller for vehicle-mounted electronic systems, including: AHB interface conversion module, memory register, interrupt manager, bus sampler, RX buffer, multiple TXT buffers, TX arbiter and CAN protocol core module, because the CAN FD controller separates the data sending process and the data receiving process to avoid the mutual influence between the two; at the same time, the CAN FD controller provided by the present invention redivides the functions of each module and can optimize the work according to the requirements of the protocol specification. process.

In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "plurality" means two or more than two, unless otherwise explicitly and specifically limited.

In the description of this specification, reference to the terms "one embodiment," "some embodiments," "an example," "specific examples," or "some examples" or the like means that specific features are described in connection with the embodiment or example. , structures, materials or features are included in at least one embodiment or example of the invention. In this specification, the schematic expressions of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may join and combine the different embodiments or examples described in this specification.

Although the present application has been described herein in connection with various embodiments, in practicing the claimed application, those skilled in the art will understand and understand by reviewing the drawings, the disclosure, and the appended claims. Other variations of the disclosed embodiments are implemented. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit may perform several of the functions recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not mean that a combination of these measures cannot be combined to advantageous effects.

The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be concluded that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all of them should be regarded as belonging to the protection scope of the present invention.

Claims (7)

1. A CAN FD controller for vehicle-mounted electronic systems, characterized by including: AHB interface conversion module, memory register, interrupt manager, bus sampler, RX buffer, multiple TXT buffers, TX arbiter and CAN protocol core module; among them, The AHB interface conversion module is used to read and write the memory register, the RX buffer and the TXT buffer; The memory register is used to store received and sent data to obtain bit data; The interrupt manager is used to monitor the status of the CAN FD IP and send interrupt information when a preset situation occurs; The bus sampler is used to receive data and send data; The TXT buffer is used to access bit data from the memory register through the memory bus of the CAN FD controller, and after inserting the frame data into its own buffer, store the single frame data in the internal RAM and transmit it to the TX Arbiter; The TX arbiter is used to determine a target TXT buffer from the plurality of TXT buffers, and send the frame data in the target TXT buffer to the CAN protocol core module; The CAN protocol core module is used to perform parallel-to-serial conversion on the received frame data, and send the obtained serial data to the bus sampler, so that the bus sampler sends the serial data row data. 2. The CAN FD controller for vehicle-mounted electronic systems according to claim 1, further comprising a frame filter; The CAN protocol core module is also used to perform serial-to-parallel conversion on the frame data, and send the obtained parallel data to the frame filter. 3. The CAN FD controller for vehicle-mounted electronic systems according to claim 2, characterized in that, The frame filter is used to filter the valid data of the RX buffer according to the CAN identifier in the received parallel data, and send the valid data to the RX buffer; The RX buffer is used to store the valid data. 4. The CAN FD controller for vehicle-mounted electronic systems according to claim 3, further comprising a prescaler; The prescaler is used to generate timing information required for CAN FD protocol transmission, and send the timing information to the AHB interface conversion module, the memory register, the interrupt manager, and the bus sampling , the plurality of TXT buffers, the TX arbiter, the CAN protocol core module, the frame filter and the RX buffer. 5. The CAN FD controller for vehicle-mounted electronic systems according to claim 1, characterized in that the TX arbiter is specifically used to determine the current status and preset priority of each TXT buffer and each TXT buffer. The type of frame data in the buffer and the size of the identifier determine the target TXT buffer, and the frame data in the target TXT buffer is sent to the CAN protocol core module. 6. The CAN FD controller for vehicle-mounted electronic systems according to claim 1, characterized in that the interrupt manager is specifically used to monitor the status of the CAN FD IP and report to all the preset situations when a preset situation occurs. The on-chip system or memory register where the CAN FD controller is located sends interrupt information. 7. The CAN FD controller for vehicle-mounted electronic systems according to claim 1, characterized in that the bus sampler is also used to detect the transmission delay time of received data and transmitted data, and to detect the received data and transmitted data. Are there any bit errors?