KR101272886B1 - apparatus and method for transmitting data with clock information - Google Patents

Abstract

The present invention relates to a method and apparatus for transmitting data with clock information, and more particularly, to the method and apparatus for transmitting a transmission signal corresponding to data bits and having a periodic transition.

An aspect of the present invention provides an apparatus for communicating data bits, comprising: a transmitter for generating a transmission signal corresponding to the data bits and having a periodic transition; A data line carrying the transmission signal; And a receiving unit generating a receiving clock signal from the periodic transition of the transmission signal (hereinafter referred to as a reception signal) transmitted through the data line, and sampling the reception signal according to the reception clock signal to restore the data bits. It provides a device having a.

Description

Apparatus and method for transmitting data with clock information}

The present invention relates to a method and apparatus for transmitting data with clock information, and more particularly, to the method and apparatus for transmitting a transmission signal corresponding to data bits and having a periodic transition.

As a conventional technology of an interface between a timing controller of a display and a data driver, there is a point-to-point differential signaling (PPDS) scheme announced by National Semiconductor.

1 is a diagram for explaining a PPDS scheme. Referring to FIG. 1, the PPDS scheme is characterized in that an independent data line 3 is connected between the timing controller 1 and each data driver 2. The PPDS scheme has an advantage of reducing EMI and reducing the total number of signal lines as compared to the conventional reduced swing differential signaling (RSDS) and low voltage differential sibling (mini-LVDS) schemes. The clock line 4 and the load line 5 are connected between the timing controller 1 and the data drivers 2. The clock line 4 and the load line 5 are commonly connected to the data drivers 2. Since differential signaling is used for the transmission of the data signal and the clock signal, the data line 3 and the clock line 4 each consist of a differential pair.

The above described PPDS scheme has some room for improvement.

First, in the PPDS scheme, a clock line is required separately from the data line. More specifically, since the clock signal is transmitted from the timing controller 1 to the data driver 2 through a separate line different from the data signal, a clock line for transmitting the clock signal is required, which increases the complexity of the wiring and , Increase display manufacturing costs.

Second, in the PPDS scheme, the high frequency clock signal transmitted through the clock line increases the EMI component.

Third, in the PPDS scheme, if a skew exists between a data signal transmitted through a data line and a clock signal transmitted through a clock line, an error may occur in a data sampling process.

Accordingly, the technical problem to be solved by the present invention is to provide a method and apparatus for transmitting a data with the clock information, so that a separate clock line is not required.

In addition, the technical problem to be solved by the present invention is to provide a method and apparatus that can remove the EMI component generated from a separate clock line by transmitting data with the clock information.

In addition, the technical problem to be solved by the present invention is to provide a method and apparatus that can solve problems such as skew, relative jitter, etc. by transmitting data with the clock information.

As a technical means for achieving the above object, a first aspect of the present invention is an apparatus for communicating data bits, the transmitter for generating a transmission signal corresponding to the data bits and having a periodic transition (periodic transition) ; A data line carrying the transmission signal; And a receiving unit generating a receiving clock signal from the periodic transition of the transmission signal (hereinafter referred to as a reception signal) transmitted through the data line, and sampling the reception signal according to the reception clock signal to restore the data bits. It provides a device having a.

According to a second aspect of the present invention, there is provided a transmission unit for transmitting data bits, comprising: a driver unit generating a transmission signal corresponding to the transmission bits; And a dummy bit interposed between the data bits, the dummy bit having a value that causes the transmission signal to have a periodic transition, thereby obtaining the transmission bits.

According to a third aspect of the present invention, a receiver corresponding to data bits and restoring data bits from a received signal having a periodic transition includes: a clock generator for generating a received clock signal from the periodic transition of the received signal; And a sampler configured to recover the data bits by sampling the received signal according to the received clock signal.

A fourth aspect of the invention is a method for communicating data bits, comprising: (a) generating a transmission signal corresponding to the data bits and having a periodic transition; (b) transmitting the transmission signal; And (c) generating a received clock signal according to the periodic transition of the transmitted transmission signal (hereinafter referred to as a received signal), and sampling the received signal according to the received clock signal to restore the data bits. It provides a method for providing.

A fifth aspect of the invention provides a transition of a first input signal, wherein the transition of the first input signal comprises a rising edge and a falling edge of the first input signal, and a second input signal—the transition of the second input signal. A method for detecting a time difference between transitions of a second input signal comprising at least one of a rising edge and a falling edge, the method comprising: (a) outputting a first signal indicating no transition difference; (b) when a transition of any one of the first input signal and the second input signal occurs, a second signal-the second signal is the first of the first input signal and the second input signal; And a third signal, wherein the third signal is a signal corresponding to a transition from the first input signal and the second input signal to the second input signal. Outputting a signal corresponding to any one of transitions to any one of the input signals; And (c) outputting the first signal when a transition of the other one of the first input signal and the second input signal occurs.

Method and apparatus for transmitting data with the clock information according to the present invention has the advantage that the clock information can be transmitted without a separate clock line separate from the data line.

In addition, the method and apparatus for transmitting data with the clock information according to the present invention has the advantage that the EMI component generated from a separate clock line is removed.

In addition, the method and apparatus for transmitting data together with the clock information according to the present invention has an advantage that the problem such as skew or relative jitter does not occur because the clock information is provided with the data.

In addition, the method and apparatus for transmitting data together with the clock information according to the present invention may be applied to various electronic devices, in particular, an interface between a timing controller and a data driver.

2 is a diagram illustrating a communication device according to an embodiment of the present invention. Referring to FIG. 2, the communication device includes a transmitter 10, a data line 20, and a receiver 30.

The transmitter 10 generates a transmission signal corresponding to the data bits and having a periodic transition. The data bits can contain various information. In one example, the data bits may include image information. As another example, the data bits may include various control information. As another example, the data bits may include information that may be used for error detection and / or error correction. The periodic transition may be caused by, for example, a dummy bit inserted every L data bits (L is an integer of 2 or more).

The data line 20 transmits the transmission signal generated by the transmitter 10 to the receiver 30. Single-ended signaling using one line may be used to transmit the transmission signal, and differential signaling using two lines such as LVDS may be used.

The receiver 30 generates a reception clock signal from a periodic transition of a transmission signal (hereinafter referred to as a reception signal) transmitted to the receiver 30 through the data line 20. In addition, the receiver recovers the data bits by sampling the received signal according to the received clock signal.

3 is a diagram corresponding to data bits and illustrating examples of a transmission signal having a periodic transition. In the drawing, data bits to be transmitted through the data line 20 are '10101100100011100' in binary. The transmission signal transmitted through the actual data line 20 is a signal in which dummy bits are added to the data bits. If the data line 20 is a differential pair, the transmission signal indicated by the solid line and the transmission signal indicated by the dotted line are transmitted through the differential line. If the data line 20 is a single line, the transmission signal indicated by the solid line and Any one of the transmission signals indicated by the dotted line is transmitted through a single line.

FIG. 3A is a diagram illustrating an example in which one dummy bit is inserted for every eight data bits. In particular, FIG. 3A illustrates a case in which the dummy bit has a different value from the data bit immediately before the dummy bit. Therefore, the value of the first dummy bit is '0' which is different from the value '1' of the data bit immediately before the first dummy bit. The value of the second dummy bit is '0' which is different from '1' which is the value of the data bit immediately before the second dummy bit. The value of the third dummy bit is '1' which is different from '0' which is the value of the data bit just before the third dummy bit. When the dummy bit is inserted in this way, a periodic transition occurs as shown in the figure. Whether the periodic transition is the rising transition or the falling transition is determined by the data bit immediately before the dummy bit. Thus, continuously transmitting data bits results in rising and falling transitions.

FIG. 3B is a diagram illustrating an example in which one dummy bit is inserted for every eight data bits. In particular, FIG. 3B illustrates a case in which the dummy bit has a different value from the data bit immediately after the dummy bit. Therefore, the value of the first dummy bit is '0' which is different from the value '1' of the data bit immediately after the first dummy bit. The value of the second dummy bit is '0', which is different from the value '1' of the data bit immediately after the second dummy bit. The value of the third dummy bit is '1' which is different from '0' which is the value of the data bit immediately after the third dummy bit. When the dummy bit is inserted in this way, a periodic transition occurs as shown in the figure. Whether the periodic transition is the rising transition or the falling transition is determined by the data bits immediately after the dummy bit. Thus, continuously transmitting data bits results in rising and falling transitions.

FIG. 3C is a diagram illustrating an example in which two dummy bits are inserted every eight data bits. The two dummy bits to be inserted have a predetermined value. When the dummy bit is inserted in this way, a periodic transition occurs as shown in the figure. Whether the periodic transition is the rising transition or the falling transition is determined by the predetermined value. If the predetermined value is '01' in binary as shown in the figure, only the rising transitions continuously occur. If the predetermined value is '10' in binary, unlike the figure only falling transitions continuously occur. As such, when two dummy bits are inserted for every L data bits, the structure of the receiver 30, in particular, the phase detector is simplified, compared to the case where one dummy bit is inserted for every L data bits. The disadvantage is that the operating frequency is increased.

4 is a diagram illustrating an example of the transmitter 10 shown in FIG. 2. Referring to FIG. 4, the transmitter includes a dummy bit inserter 11 and a driver 12.

The dummy bit inserting unit 11 generates transmission bits by periodically inserting one or several dummy bits between the input data bits. The transmission signal has a periodic transition by one or several dummy bits.

The dummy bit inserter 11 includes, for example, an inverter 16 and a parallel-to-serial converter 17. The inverter 16 inverts the value of one data bit [1] of data bits consisting of eight bits. The parallel-to-serial converter 17 receives in parallel nine data bits (data bits [8: 1]) consisting of eight bits and output bits of the inverter 16 including one bit. In addition, the parallel-to-serial converter 17 sequentially outputs the received nine bits by one bit. For example, when data bits [8: 1] are '01011001' in binary, '010110010' is input in parallel to the parallel-serial converter 17 and the parallel-serial converter 17 ), '0', '1', 0 ',' 1 ',' 1 ',' 0 ',' 0 ',' 1 'and' 0 'are sequentially output. When the dummy bit insertion unit 11 is configured in this way, one dummy bit is inserted for every eight data bits, and the dummy bit inserter 11 can generate a transmission signal having a different value from the data bit immediately before the dummy bit.

When one dummy bit is inserted for every eight data bits, and a dummy bit is to generate a transmission signal having a value different from that of the data bit immediately after the dummy bit, unlike in the figure, the parallel-to-serial converting unit is the most significant data bit ( The inversion of the data bits [8]) and the data bits [8: 1] are inputted, and the inversion of the most significant data bits [data bits [8] is output first, and then the data bits [data bits [ 8: 1]) in order from the most significant bit.

In the case where it is desired to generate a transmission signal in which two dummy bits are inserted for every eight data bits, unlike in the figure, the parallel-to-serial conversion section includes data bits (data bits [8: 1]) and predetermined dummy bits ( For example, '01' is input as a binary number, and the data bits (data bits [8: 1]) are sequentially output from the most significant bit, and then predetermined dummy bits are sequentially output from the most significant bit.

The driver 12 outputs a transmission signal (for example, an LVDS signal) corresponding to the transmission bits. The transmission signal output from the driver 12 is applied to the data line 20.

FIG. 5 is a diagram illustrating an example of the receiver 30 illustrated in FIG. 2. Referring to FIG. 5, the receiver 30 includes a clock generator 31 and a sampler 32.

The clock generator 31 generates a received clock signal from a periodic transition of the received signal transmitted through the data line 20. Thus, the received clock signal has a period corresponding to the period of periodic transition of the received signal. In one example, the receive clock signal has a period equal to a period of periodic transitions, and is composed of L clocks that are out of phase with each other (L is the number of data bits present between two consecutive periodic transitions). It may be. In this case, the sampler 32 uses the L clocks to sample the L data bits. As another example, the received clock signal may be an integer multiple of the frequency of periodic transitions (an inverse of the period of periodic transitions) (for example, (L + M) times when M dummy bits are inserted for every L data bits). It may be composed of one clock having a frequency corresponding to. In this case, sampler 32 uses one clock to sample the L data bits.

The sampler 32 restores the data bits by sampling the received signal according to the received clock signal.

FIG. 6 is a diagram illustrating an example of the clock generator 31 illustrated in FIG. 5. FIG. 7 is a diagram illustrating an example of main signals represented in FIG. 6. 6 and 7, the clock generator 31 includes a transition detection circuit 40 and an oscillator 50.

The transition detection circuit 40 outputs a signal DIFF corresponding to the time difference between the periodic transition of the received signal and the transition of the feedback clock signal FC. The transition detection circuit 40 includes, for example, a transition detector 41, an enable signal generator 42, and a low pass filter 43.

The transition detector 41 outputs signals UP and DN corresponding to the time difference between the transition of the received signal and the transition of the feedback clock signal FC. As the transition detector 41 calculates the time difference between the transition of the received signal and the transition of the feedback clock signal FC, the transition and the feedback of the period during which the enable signal EN is applied among the various transitions of the received signal. The transition of the period in which the enable signal EN is applied is used among the various transitions of the clock signal FC.

The enable signal generator 42 generates the enable signal EN to cause the transition detector 41 to operate according to a periodic transition caused by the dummy bit among several transitions of the received signal. Accordingly, the transition detector 41 has a time between the transition of the received signal input in the period when the enable signal EN is applied and the transition of the feedback clock signal FC input in the period during which the enable signal EN is applied. Get a car. In addition, the transition detector considers the transition of the received signal input in the period when the enable signal EN is not applied and the transition of the feedback clock signal FC input in the period when the enable signal EN is not applied. Not.

T is the time at which the periodic transition is performed, P is the period of periodic transitions, N is the number of bits received during P (N is the number of data bits located between two consecutive periodic transitions, L is 2 consecutive). If the number of at least one dummy bit located between the two periodic transitions is M, N is L + M). Preferably, T_START, which is a start point of the enable signal, and an end point of the enable signal, T_END satisfies Equation 1 below.

T-(P / N) <T_START <T

T <T_END <T + (P / N)

If the start time T_START is less than or equal to [T-(P / N)] or the end time T_END is more than or equal to [T + (P / N)], within the period during which the enable signal EN is applied, There are unwanted transitions in the received signal other than periodic transitions. In addition, when the start time T_START is greater than T or the end time T_END is less than T, there is no periodic transition within the period during which the enable signal EN is applied. In the figure, an example is shown when the start time point is [T-(P / 2N)] and the end time point is [T + (P / 2N)].

The enable signal generator 42 generates the enable signal EN according to at least one of various delay clocks that can be obtained from the delay line 51. In the drawing, an example in which the enable signal generation unit 42 receives the first delayed clock DC1 output from the first inverter I1 and the seventeenth delayed clock DC17 output from the seventeenth inverter I17 is represented. have. The first delayed clock DC1 is a signal in which the inversion of the feedback clock signal FC is delayed by (P / 2N), and the seventeenth delayed clock DC17 has an inversion of the feedback clock signal FC-(P / 2N). As long as the signal is delayed. The enable signal generator 42 includes an inverter INV and an AND operator AND to generate an enable signal EN from the first delay clock DC1 and the seventeenth delay clock DC17. .

The low pass filter 43 obtains a signal DIFF from which the high frequency components of the signals UP and DN corresponding to the transition difference output from the transition detector 41 are removed or reduced. The low pass filter 43 may be, for example, a charge pump.

The oscillator 50 changes the phases of the feedback clock signal FC and the received clock signal according to the signal DIFF output from the transition detection circuit 40. Oscillator 50 includes, for example, a delay line 51 and a feedback line 52.

The delay of the delay line 51 is changed in accordance with the signal DIFF output from the transition detection circuit 40. The delay line 51 includes a plurality of inverters I1 to I18. The delay of each of the plurality of inverters I1 to I18 is adjusted according to the signal DIFF output from the transition detection circuit 40. Each of the plurality of inverters I1 to I18 has a delay corresponding to approximately (P / 2N). Third, fifth, fifth, seventh, ninth, eleventh, thirteenth, fifteenth, and seventeenth inverters I3, I5, I7, I9, I11, I13, I15, and I17 respectively outputted from the third and fifth. , Seventh, ninth, eleventh, thirteenth, fifteenth, and seventeenth delayed clocks DC3, DC5, DC7, DC9, DC11, DC13, DC15, and DC17 are output to the sampler 32 as a received clock signal.

The feedback line 52 feeds back the feedback clock signal FC output from the delay line 51 to the input of the delay line 51.

FIG. 8 is a diagram illustrating an example of the transition detection unit 41 shown in FIG. 6. Referring to FIG. 8, the transition detector 41 may include first to third D flip-flops FF1, FF2, and FF3, first and second logical OR operators OR1 and OR2, logical AND operator AND, and an inverter ( INV).

The first flip-flop FF1 is a positive edgge triggered D flip-flop. The input terminal D, the clock terminal CLK, and the reset terminal RS of the first flip-flop FF1 have a signal corresponding to bit '1' (for example, a power supply voltage VDD), a received signal, and a second signal. The outputs of the OR operator OR2 are input respectively. Therefore, the first flip-flop FF1 outputs '0' after the output of the second logical OR operator OR2 becomes '1'. The first flip-flop FF1 outputs '1' after the rising edge of the received signal occurs in the state where the output of the second logical OR operator is '0'.

The second flip-flop FF2 is a negative edgge triggered D flip-flop. The input terminal D, the clock terminal CLK, and the reset terminal RS of the second flip-flop FF2 each have a signal corresponding to bit '1', an output signal, and an output of the second OR circuit OR2, respectively. Is entered. Therefore, the second flip-flop FF2 outputs '0' after the output of the second logical OR operator OR2 becomes '1'. The second flip-flop FF2 outputs '1' after the falling edge of the received signal occurs while the output of the second logical OR operator is '0'.

The third flip-flop FF3 is a positive edgge triggered D flip-flop. The input terminal D, the clock terminal CLK, and the reset terminal RS of the third flip-flop FF3 have a signal corresponding to bit '1', a feedback clock signal FC, and a second logical sum operator OR2. Are respectively inputted. Therefore, the third flip-flop FF3 outputs '0' after the output of the second logical OR operator OR2 becomes '1'. The third flip-flop FF3 outputs '1' after the rising edge of the feedback clock signal FC occurs in the state where the output of the second logical OR operator is '0'.

The first logical OR operator OR1 receives an output of the first flip-flop FF1 and an output of the second flip-flop FF2. The second OR operation OR2 receives an output of the inverter INV and an output of the AND product AND. The AND product AND receives the output of the first AND operator OR1 and the output of the third flip-flop FF3. The inverter INV receives the enable signal EN.

The transition detector 41 shown in FIG. 8 operates as follows by having such a configuration.

First, '1' is applied to the reset terminals RS of the first to third flip-flops FF1, FF2, and FF3 during the period when the enable signal is not applied, and thus, the first to third flip-flops ( FF1, FF2, and FF3) output '0'. Therefore, the transition difference signals UP and DN become (0, 0). If the transition difference signals UP and DN are (0, 0), there is no transition difference. Even when the enable signal EN is applied, the transition difference signals UP and DN are equal to (0, 0) before at least one of the rising edge of the reception signal, the falling edge of the reception signal, and the rising edge of the feedback clock FC occurs. 0) Maintain state.

When the enable signal EN is applied and the transition difference signals UP and DN are (0, 0), when one of the rising edge of the received signal and the falling edge of the received signal occurs, the transition difference signal ( UP, DN) becomes (1, 0). When the enable signal EN is applied and the rising edge of the feedback clock FC is generated while the transition difference signals UP and DN are (1, 0), the transition difference signals UP and DN are ( 0, 0).

Further, when the enable signal EN is applied and the rising edge of the feedback clock FC is generated while the transition difference signals UP and DN are (0, 0), the transition difference signals UP and DN are generated. Becomes (0, 1). When the enable signal EN is applied and the transition difference signals UP and DN are (0, 1), when one of the rising edge of the received signal and the falling edge of the received signal occurs, the transition difference signal ( UP, DN) becomes (0, 0).

If the transition detector 41 always operates irrespective of the enable signal EN, the inverter INV and the second OR operation OR2 are omitted in FIG. 8, and the output of the AND operator is immediately output. It is input to the reset stage RS of the first to third flip-flops FF1, FF2, and FF3. In this case, the transition detector operates as follows according to the transition of the received signal and the transition of the feedback clock FC. Here, the transition of the received signal includes the rising edge and the falling edge of the received signal, and the transition of the feedback clock FC includes only the rising edge of the feedback clock FC. However, if one double-ended D flip-flop, one negative-ended D flip-flop, and an OR operator are used in place of the third flip-flop FF3, the transition of the feedback clock FC becomes the feedback clock FC. It may be to include the rising edge and the falling edge of.

In the state where the transition difference signals UP and DN are (0, 0), when a transition between any one of the received signal and the feedback clock signal FC occurs, (1, 0) and (0, 1) The transition difference signals UP and DN having any one of the values are output. More specifically, when the transition of the received signal occurs, the transition difference signals UP and DN having the value of (1, 0) are output, and when the transition of the feedback clock signal FC occurs, (0, Transition difference signals UP and DN having a value of 1) are output.

Then, when a transition of the other one of the received signal and the feedback clock signal FC occurs, the transition difference signals UP and DN having a value of (0, 0) are output.

In an embodiment of the present invention, in order for the rising edge of the feedback clock signal FC to be located within a period during which the enable signal EN is applied, initial synchronization of the feedback clock signal FC is required. For the initial synchronization of the feedback clock signal FC, a transmission clock signal having a period (for example, the same period) corresponding to the period of periodic transition of the transmission signal needs to be transmitted from the transmitter 10 to the receiver 30. . The transmission clock signal may be transmitted through a line separate from the data line 20, but is preferably transmitted through the data line 20. More specifically, initially, the transmission unit 10 generates a transmission clock signal, and transmits the generated transmission clock signal to the reception unit 30 through the data line 20. The receiver 30 adjusts phases of the feedback clock signal FC and the received clock signal according to the received transmission clock signal. After the receiver 30 acquires the initial synchronization, the transmitter 10 corresponds to the data bits through the data line 20 and transmits a transmission signal having a periodic transition to the receiver 30.

In order to transmit the transmission clock signal, the transmitter 10 periodically applies a predetermined value (for example, '11110000') to the data bits [8: 1] of FIG. 4 to periodically shift the transmission signal. A transmit clock signal having the same period and the same phase as is generated.

In order for the receiver 30 to acquire initial synchronization from the received transmission clock signal, the clock generator 31 shown in FIG. 6 and the transition detector 41 shown in FIG. 31 and the cloth shown in FIG. 10 may be replaced with the detection unit 41.

The clock generator 31 shown in FIG. 9 further includes a switch 53 as compared to the clock generator 31 shown in FIG. The switch 53 outputs, to the delay line 51, any signal selected according to the selection signal INI among the reception signal and the feedback clock signal FC. More specifically, the switch 53 outputs a received signal during an initial synchronization acquisition period, and outputs a feedback clock signal FC after the initial synchronization is acquired.

The transition detector 41 shown in FIG. 10 further includes first and second switches SW1 and SW2 as compared with the transition detector 41 shown in FIG. 8. The first switch SW1 outputs one signal selected according to the output of the second flip-flop FF2 and the selection signal INI among '0' to the first OR logic OR1. More specifically, the first switch SW1 outputs '0' during an initial synchronization period, and outputs an output of the second flip-flop FF2 after the initial synchronization is acquired. The second switch SW2 outputs any signal selected according to the enable signal EN and the selection signal INI among '1' to the inverter INV. More specifically, the second switch SW2 outputs '1' during the period of initial synchronization acquisition, and outputs the enable signal EN after the initial synchronization is acquired.

1 is a view for explaining the PPDS method which is a type of data communication method according to the prior art.

2 is a diagram illustrating a communication device according to an embodiment of the present invention.

3 is a diagram corresponding to data bits and illustrating examples of a transmission signal having a periodic transition.

4 is a diagram illustrating an example of the transmitter 10 shown in FIG. 2.

FIG. 5 is a diagram illustrating an example of the receiver 30 illustrated in FIG. 2.

FIG. 6 is a diagram illustrating an example of the clock generator 31 illustrated in FIG. 5.

FIG. 7 is a diagram illustrating an example of main signals represented in FIG. 6.

FIG. 8 is a diagram illustrating an example of the transition detection unit 41 shown in FIG. 6.

9 and 10 are diagrams each showing another example of the clock generator 31 and the transition detector 41, respectively.

Claims (18)

An apparatus for communicating data bits, the apparatus comprising: A transmitter for generating a transmission signal corresponding to the data bits and having a periodic transition; A data line carrying the transmission signal; And A receiver configured to generate a reception clock signal from the periodic transition of the transmission signal (hereinafter referred to as a reception signal) transmitted through the data line, and to sample the reception signal according to the reception clock signal to restore the data bits. Equipped, The receiver may further comprise: A transition detector for outputting a signal corresponding to a time difference between the periodic transition of the received signal and the transition of a feedback clock signal, and enabling the transition detector to operate only according to the periodic transition among several transitions of the received signal And an enable signal generator for providing a signal and an oscillator for changing phases of the feedback clock signal and the received clock signal according to a signal corresponding to the time difference. The method according to claim 1, Wherein the periodic transition is caused by a dummy bit inserted every L data bits of the data bits (L is an integer of 2 or more). 3. The method of claim 2, And the dummy bit has a different value from the data bit just before the dummy bit among the data bits. 3. The method of claim 2, The dummy bit has a different value from the data bit immediately after the dummy bit among the data bits. delete delete delete delete delete delete delete delete A method for communicating data bits, the method comprising: (a) generating a transmission signal corresponding to the data bits and having a periodic transition; (b) transmitting the transmission signal; And (c) generating a received clock signal according to the periodic transition of the transmitted transmission signal (hereinafter referred to as a received signal), and sampling the received signal according to the received clock signal to recover the data bits. , Step (c) provides an enable signal that operates only according to the periodic transition among the multiple transitions of the received signal, and the periodic transition of the received signal and the transition of the feedback clock signal according to the enable signal. Outputting a signal corresponding to a time difference therebetween; Changing a phase of the feedback clock signal and the received clock signal in accordance with a signal corresponding to a time difference between the periodic transition of the received signal and the transition of a feedback clock signal. 14. The method of claim 13, The periodic transition is caused by a dummy bit inserted every L (L is an integer of 2 or more) of the data bits. 15. The method of claim 14, And wherein the dummy bit has a different value from the data bit just before the dummy bit among the data bits. 15. The method of claim 14, And wherein the dummy bit has a different value from the data bit immediately after the dummy bit among the data bits. 14. The method of claim 13, Wherein the transmission signal is transmitted in single-ended signaling using one line or differential signaling using two lines. delete

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