TWM603559U - Data-reading device - Google Patents

Abstract

A data reading device includes: an oscillator; a first counter for counting a plurality of sampling points to obtain a first count value; and a control unit for executing: oversampling the digital signal Work, and calculate the sampling points according to the oversampling operation; define a second count value corresponding to the first count value; perform the oversampling operation for the second count value on the data signal as a unit Interval; define a data reading range; and within the data reading range, when the potential of the counted sampling points changes from the first potential to the second potential, it is determined that the data of a data signal is the first value, when When the potential of the sampling points changes from the second potential to the first potential, it is determined that the data of the data signal is a second value.

Description

Data reading device

The present disclosure relates to the field of audio-visual interfaces, and particularly relates to a method for reading data and a data reading device.

DisplayPort is a digital multimedia interface standard formulated by the Video Electronics Standards Association (VESA). In the DisplayPort specification, the signal channel includes a main link and an auxiliary channel. The main link is used to transmit image data and is a high-speed one-way output. The auxiliary channel includes a pair of auxiliary signals to transmit information other than image data, such as status information about the sending device and the receiving device, commands for controlling the sending device and the receiving device, audio, etc. It is a low-speed two-way communication. It serves as the communication between the sending device and the receiving device before the main link starts to transmit image data.

Figure 1 shows a conventional system architecture diagram of the DisplayPort interface. As shown in Figure 1, the DisplayPort interface includes a main link 30, an auxiliary channel 31 and a hot plug detect (HPD) signal line 32. Among them, the auxiliary channel 31 provides a transmission bandwidth of 1 Mbps, which is used for bidirectional transmission between the source device 1 and the sink device 2.

In the existing chip design, in order to save cost and power, a design method without phase-locked loops (PLL) is adopted. Therefore, if it is necessary to sample the transmission signal of the auxiliary channel 31, a ring oscillator clock can be used to sample the transmission signal. However, this design method sometimes causes the sampling frequency to vary due to the pressure, temperature, and instantaneous voltage of the circuit in the operating environment, resulting in fluctuations or inaccuracy of the sampling frequency. For example, if the preset frequency of the ring oscillator is 10MHz, the actual sampling frequency of the ring oscillator is only 8MHz due to the influence of air pressure, voltage, and temperature in the operating environment, which does not reach the ideal value (ie 10MHz). Or, the sampling frequency of the first time is 8MHz, and the sampling frequency of the second time is 8.5MHz, which causes the phenomenon of frequency fluctuation. Since the sampling frequency of a conventional ring oscillator has a very large variation range, it is a great challenge to correctly acquire data.

The present disclosure provides a data reading device that can synchronize a digital signal by using an over-sampling method for sampling at a high multiple frequency, and accurately capture data.

A data reading device of the present disclosure is used for reading data of a digital signal having a first frequency, wherein the digital signal includes a synchronization signal and a data signal. The data reading device includes: an oscillator, To generate a second frequency, wherein the second frequency is greater than the first frequency; a first counter for counting the sampling points to obtain a first count value; and a control unit for executing: The second frequency performs an oversampling operation on the digital signal, and calculates a plurality of sampling points according to the oversampling operation; defines a second count value corresponding to the first count value; uses the second frequency to The over-sampling operation of the data signal for the second count value is a unit interval (Unit Interval, UI); within the unit interval, a data reading range is defined; and within the data reading range, when counting When the potentials of the sampling points change from a first potential to a second potential, it is determined that the data signal corresponding to the unit interval is a first value. When the potentials of the sampling points counted change from the second When the potential changes to the first potential, it is determined that the data signal corresponding to the unit interval is a second value, wherein the first potential is different from the second potential, and the first value is different from the second value .

In one embodiment, the control unit is further configured to perform: when the potential of the sampling points counted in the data reading range is changed from the first potential to the second potential or from the second potential to the first potential At a potential, the count value of the sampling point at which the potential transitions is recorded and defined as the first count value, and the count value of the first counter is ordered to reset to 0.

In one embodiment, the control unit is further configured to perform: perform the over-sampling operation on the synchronization signal to obtain the first count value before the data signal is transmitted; when the potential of the sampling points of the count is changed by When the first potential changes to the second potential, record the count value corresponding to the sampling point of the potential change, and instruct the count value of the first counter to reset back to 0 and re-count; and when the re-counted When the potential of the sampling point changes from the first potential to the second potential again, it is determined whether the count value corresponding to the sampling point of the current potential transition is twice or more than the count value of the previous record; if yes , Define the count value of this record as the first count value, and instruct the count value of the first counter to reset back to 0, and then perform the transmission of the data signal.

In one embodiment, the control unit is further configured to perform: when the potential of the sampling points that are transmitted and counted are changed from the first potential to the second potential, determine the sampling point of the current potential transition Whether the corresponding count value is twice or more than the previous count value; if it is, the transmission of the data signal is terminated.

In one embodiment, the data reading device further includes a register, and the control unit is further used for executing: counting the first counter corresponding to the sampling point of the potential transition in each data reading range The count value is correspondingly defined as the second count count value; and the register is made to store the second count count value.

In one embodiment, the data reading device further includes a second counter, counting the data signal during the oversampling operation according to the second count value, and the control unit further according to the first counter within the unit interval Perform the over-sampling operation on the data signal with the second count value, and when the unit interval ends, command the second counter to reset to 0.

In an embodiment, the control unit is further configured to execute: define the count times i to j of the second counter as the data reading range; wherein the count times i is calculated by a formula: i = (m÷4) + k is calculated, the count number j is calculated by a calculation formula: j = i + (m÷2), where m is the second count value; when the remainder of m÷4 is 0 to 2, k is 0; When the remainder of m÷4 is 3, k is 1.

In one embodiment, the control unit is further configured to perform: when the potential of the sampling points counted in the data reading range is changed from the first potential to the second potential or from the second potential to the At the first potential, compare the corresponding count value of the first counter and the second counter at the sampling point of the potential transition; if the count value of the second counter at the sampling point of the potential transition is greater than one-half If the count value of the first counter at the sampling point of the potential transition is increased, the count number of the second counter is increased; and if the count value of the second counter at the sampling point of the potential transition is less than one-half The number of times the first counter counts at the sampling point of the potential transition is reduced by the number of counts of the second counter; wherein, according to one-half of the number of times the first counter counts at the sampling point of the potential transition and The second counter increases or decreases the count number of the second counter by the difference of the count value of the sampling point of the potential transition.

In one embodiment, there is a functional relationship between the first count value and the second count value.

In an embodiment, the second frequency is n times the first frequency, and n is an integer greater than one.

FIG. 2A shows a timing diagram of a digital signal of the present disclosure. FIG. 2B shows an enlarged timing diagram of the data signal in FIG. 2A. As shown in FIG. 2A, the digital signal 10 transmitted on the auxiliary channel 31 (as shown in FIG. 1) includes a synchronization signal 10' and a data signal 10''. The synchronization signal and the data signal will be described in detail in Figure 3A. Please refer to FIG. 2A first. In one embodiment, the synchronization signal 10' and the data signal 10'' are transmitted in the signal synchronization phase T1 and the data transmission phase T2, respectively. For example, in the signal synchronization phase T1, the clock signal 21 at the receiving end continuously tracks the digital signal 10 to achieve frequency synchronization, and when the receiving end receives the synchronization end signal 101 of the digital signal 10, it is ready to enter the data transmission phase T2. Then, in the data transmission stage T2, the receiving end samples the data signal 10" of the digital signal 10 in each clock cycle C (as shown in Figures 2A and 2B), and when the sampled data signal 10" changes from high VGH turns into a low potential VGL, and the data of the data signal 10" is read as 1 by the receiving end. In contrast, when the sampled data signal 10'' changes from a low potential VGL to a high potential VGH, the data of the data signal 10'' is read as 0 by the receiving end. Subsequently, if the receiving end receives the synchronization end signal 101 of the digital signal 10 again (as shown in the second signal synchronization phase T1' in FIG. 2A), it means that the signal transmission operation is completed.

In summary, in order to effectively reduce cost and power consumption, and to take into account the accuracy of reading the data signal 10", the present disclosure defines a data reading range when the digital signal 10 is transmitted, and uses an over-sampling operation The digital signal 10 is sampled within the data reading range, and then the content of the data signal 10" is correctly read. The synchronization signal 10', the data signal 10'' and the above-mentioned over-sampling operation of the present embodiment will be described in detail in the following FIG. 3A.

FIG. 3A shows a schematic diagram of a digital signal using the method of reading data of the present disclosure. FIG. 3B is an enlarged view of the data signal 10'' in FIG. 3A. 4 is a flowchart of a method for reading data according to the present disclosure, which can be applied to an electronic device having a DisplayPort interface, for example. FIG. 6 shows a flowchart of the synchronization signal performing the oversampling operation according to the present disclosure. Please refer to FIGS. 3A-3B and FIG. 4 together. The method of reading data in the present disclosure includes the following steps:

First, as described in step S10, a digital signal 10 having a first frequency is received. Among them, the digital signal 10 includes a synchronization signal 10' and a data signal 10''. In this embodiment, the first frequency is 1 MHz as an example.

Then, as described in step S11, an over-sampling operation is performed on the digital signal at the second frequency, and multiple sampling points are calculated according to the over-sampling operation. In one embodiment, an oscillator is used to generate a second frequency to perform an over-sampling operation on the digital signal 10, and a plurality of sampling points 100 are calculated according to the over-sampling operation. Wherein, the second frequency is greater than the first frequency. In a preferred embodiment, the second frequency is n times the first frequency. In other embodiments, n is, for example, an integer greater than 1, but is not limited thereto. The above-mentioned oscillator can be a ring oscillator or other suitable oscillators. In this embodiment, for the convenience of description, the second frequency is described by taking 16 MHz as an example, that is, n is equal to 16.

Then, as described in step S12, a first counter 11 is used to count the sampling points 100 to obtain a first count value (such as the value 16 or 48 of the first counter 11 in FIG. 3A). It is worth mentioning that, in the process of sampling the synchronization signal 10' and the data signal 10" in this embodiment, for example, there are different ways of defining the first count value, but it is not limited to this. . Here, this article first describes the definition of the first count value when the synchronization signal 10' is sampled.

Based on the above, in this embodiment, the process of sampling the synchronization signal 10' is as shown in FIG. 6. Steps S110 to S111 shown in FIG. 6 illustrate the definition of the first count value before the data signal 10'' is transmitted. Please refer to FIGS. 3A and 6 together. First, when the potential of the counted sampling points 100 changes from the first potential to the second potential, record the number of counts corresponding to the sampling point 100 of the potential transition, and The count value of the first counter 11 is reset to 0, and counts again (step S110 in FIG. 6). Furthermore, corresponding to FIG. 3A to clearly understand that when the potential of the counted sampling points 100 changes from a high potential VGH (first potential) to a low potential VGL (second potential), for example, the sampling of the potential transition is recorded Point corresponding to the count value, and the count value of the first counter 11 will be reset back to 0 and count again.

For example, in FIG. 3A, at the time t20, the potential corresponding to the sampled point is changed from the high potential VGH to the low potential VGL, and the value of the first counter 11 is 16. Therefore, the value 16 will be recorded, and the count value of the first counter 11 will be reset to 0. Similarly, in the subsequent oversampling operation, at time t21, the sampled potential also changes from the high potential VGH to the low potential VGL. At this time, the value of the first counter 11 is 48. Therefore, a value of 48 will also be recorded.

It is worth mentioning that this embodiment will determine whether to perform the data signal 10" by determining whether the count value corresponding to the sampling point 100 of the potential transition is twice or more than the count value value recorded in the previous time. transmission. In detail, when the potentials of the re-counted sampling points 100 change from the first potential to the second potential again, if it is determined that the number of counts corresponding to the sampling point 100 of the potential transition is the count of the previous record If the value is twice or more, the count value of this record will be defined as the first count value, and the count value of the first counter is reset back to 0, and then the data signal 10'' is transmitted (Step S111 in Figure 6).

The above description can be further corresponding to FIG. 3A for a clear understanding. As shown in FIG. 3A, at time t21, the potential of sampling point 100 changes from high potential VGH to low potential VGL again, and the count value corresponding to sampling point 100 is 48, which is the count value of the previous record (ie 16) Tripled. Therefore, the first count value is defined as 48, and then the data signal 10'' is transmitted.

Then, after the first count value is obtained, as described in step S13, a second count value is correspondingly defined based on the first count value. In this embodiment, there is a functional relationship between the first count value and the second count value. The functional relationship is, for example, a linear equation y=cx, where y is the second count value, x is the first count value, and c is a constant. Similarly, this embodiment also defines different constants c before and after the data signal 10'’ is transmitted, but it is not limited thereto. For example, before the data signal 10'' is transmitted, the value of c in this embodiment is set to, for example, 1/3. Correspondingly, during the data signal 10'' transmission, the value of c can be set to 1, for example. As shown in FIGS. 3A-3B, before the data signal 10'' is transmitted (that is, the signal synchronization phase T1), the value of c is set to 1/3 in this embodiment. Therefore, at time t21 in FIG. 3A and the initial first count value is defined as a value of 48, the initial second count value is calculated as a value of 16.

Then, please refer to FIG. 3B together. After step S13, step S14 is performed to define a unit interval. Simply put, after the corresponding definition of the second count value in step S13, this embodiment will use the second frequency to perform the oversampling operation of the second count value on the data signal 10" as a unit Interval (Unit Interval, UI). For example, when the aforementioned initial first count value is defined as a value of 48 (as shown in FIG. 3A), the initial second count value is a value of 16. Based on the above-mentioned initial value of the second count value of 16, the subsequent embodiment will use a second counter 12 to count the number of sampling points to a value of 16, and the interval is The defined unit interval.

FIG. 5A shows a sub-flow chart of step S15 in FIG. 4 according to the present disclosure. Please also refer to FIG. 5A. Subsequently, after the definition of the unit interval is completed (step S14), this embodiment will proceed to step S15 shown in FIG. 4: within the unit interval, define a data reading range. In this embodiment, the data reading range is as shown by the shaded area 120 in FIG. 3B. In detail, after the transmission of the data signal 10" is started, this embodiment will perform step S150 as shown in FIG. 5A: the second counter 12 is used to count the data signal 10" during the over-sampling operation of the sampling points 100 frequency. For example, after the transmission of the data signal 10'' is started, this embodiment uses the second counter 12 to count the number of sampling points to a value of 16 in the oversampling operation (as shown in FIG. 3B). Furthermore, it can be clearly seen from FIG. 3B that, in the first unit interval UI' of this embodiment, the data signal 10'' is subjected to the oversampling operation with the second count value of 16. That is, in this embodiment, the over-sampling operation is performed on the data signal 10'' in the unit interval UI' according to the second count value 16. Wherein, after the second counter 12 counts the number of sampling points to the second count value, the second counter 12 resets back to 0, and defines the first count value according to the updated first count value. The second count value is used for subsequent count operations. Furthermore, the subsequent unit interval UI’’’ can also be defined.

As mentioned above, after performing step S150 in FIG. 5A, this embodiment will continue to perform step S151, for example: defining the count times i to j of the second counter 12 as the data reading range, so as to reach only the count times i to Read in the range of j to achieve the purpose of effectively reducing cost and power consumption. In this embodiment, the count number i is calculated by a calculation formula: i = (m÷4) + k, and the count number j is calculated by a calculation formula: j = i + (m÷2), where m Is the second count value; when the remainder of m÷4 is 0 to 2, k is 0; when the remainder of m÷4 is 3, k is 1. Taking the unit interval UI' as an example, the second count value is a value of 16. That is, m is equal to 16. The remainder of m÷4 is 0, so k is 0. Therefore, the count number i is calculated as 4 by the above formula, and the count number j is also calculated as 12 by the above formula. Therefore, the number of counts 4 to 12 of the second counter 12 is defined as the data reading range (as shown in FIG. 3B).

In order to better understand the data reading range under different unit intervals, this embodiment is illustrated with FIG. 5B. FIG. 5B illustrates the data reading range corresponding to different unit intervals of the present disclosure. As shown in FIG. 5B, in order to accurately read the data of the data signal 10'', the data reading range corresponding to each unit interval is not all the same. For example, within the unit interval where the second count value is 19, the corresponding data reading range is calculated as the count value of the second counter 12 from 5 to 14. In addition, within the unit interval where the second count value is 12, the corresponding data reading range is calculated to be the count value of the second counter 12 from 3 to 9.

Please continue to refer to FIG. 4, after completing the definition of a data reading range in step S15, step S16 is executed to read data within the data reading range. In detail, within the data reading range of each unit interval, when the potential of the counted sampling points 100 changes from a first potential to a second potential, the data signal 10" corresponds to the unit The interval data will be read as a first value. Correspondingly, when the potential of the counted sampling points 100 changes from the second potential to the first potential, the data of the data signal 10'' corresponding to the unit interval will be read as a second value. In this embodiment, the first potential is different from the second potential, and the first value is different from the second value. Furthermore, the first potential is, for example, a high potential VGH, and the second potential is, for example, a low potential VGL. In addition, the first value is, for example, 1, and the second value is, for example, 0.

Here, this embodiment further takes the unit interval UI' as an example for description. Please refer to FIG. 3B. In this embodiment, at time t30, the potential of the sampling point 100 of the data signal 10" is, for example, changed from a high potential VGH to a low potential VGL, wherein the time t30 of the sampling point 100 of the potential transition is It will be located in the data reading range of the count times of the second counter 12 from 4 to 12 (as described above). Therefore, the data of the unit interval UI' in the data signal 10'' will be read as 1. In detail, in this embodiment, the defined data reading range covers the time t30 of the sampling point 100 of the potential transition, and then the data of the unit interval UI' of the data signal 10'' is read. In this way, based on this embodiment, a data reading interval is defined during the transmission of the digital signal 10, and an oversampling operation is used to sample and read the digital signal 10 within the data reading range. Examples can effectively reduce costs and power consumption, and can take into account the accuracy of reading the data signal 10".

Similarly, in this embodiment, the data reading range defined for UI" will also cover the time t31 of the sampling point 100 of the potential transition, and the unit interval UI of the data signal 10" can also be read. data of. Specifically, in the unit interval UI'', the potential of the sampling point 100 at time t31 also changes from a low potential VGL to a high potential VGH within the defined data reading range. Correspondingly, the data of the unit interval UI’’ in the data signal 10’’ can be read as 0.

It is worth mentioning that this embodiment adopts a method of defining the first count value when sampling the synchronization signal 10' to obtain the first count value before the data signal 10'’ is transmitted. Correspondingly, in this embodiment, when the data signal 10" is transmitted, the first count value adopts another method, which is explained as follows: when the potential of the sampling points 100 counted within the data reading range When changing from a first potential to a second potential or from the second potential to the first potential, the count value of the sampling point of the potential transition is recorded and defined as the first count value. As shown in FIG. 3B, at time t30, t32, and t31, the potential of the sampling point 100 changes from a high potential VGH to a low potential VGL or from a low potential VGL to a high potential VGH. Although the foregoing embodiment has different ways of defining the first count value during the sampling operation of the synchronization signal 10' and the data signal 10'', it is not limited to this. That is, in other preferred embodiments, the first count value can also be defined in the same way during the over-sampling operation of the synchronization signal 10' and the data signal 10''.

In summary, the present embodiment defines the first count value of 16, 18, and 20 at time t30, t32, and t31, respectively. Correspondingly, the second count value can be correspondingly defined according to the first count value. In particular, as mentioned above, in this embodiment, before and after the data signal 10" is transmitted, there will be different definitions between the first count value and the second count value, and in this embodiment During the transmission of the data signal 10", the second count value is equal to the first count value. Furthermore, during the transmission of the data signal 10'', the second count value can be defined according to the corresponding first count value. Correspondingly, the unit interval and the data reading range can also be defined as the above description, and will not be repeated here.

Continuing from the above, please refer to FIGS. 3A and 6 again. When the data signal 10" is transmitted and the potentials of the sampling points 100 counted change from the first potential to the second potential, this embodiment will determine this time Whether the number of counts corresponding to the sampling points 100 of the potential transition is twice or more than the number of counts recorded in the previous record; if so, the transmission of the data signal 10" is ended (as described in step S112 in Figure 6) . As shown in Fig. 3A, at time t24, the potential of sampling point 100 changes from high potential VGH to low potential VGL again, and the count value corresponding to sampling point 100 is 48, which is the count value recorded in the previous time (ie 16) Tripled. Therefore, the transmission of the data signal 10'' is ended.

Regarding the definition of the second count value in the aforementioned step S13, this article will explain in detail here: As can be seen from the above, the definition of the second count value in this embodiment depends on two situations. Take the function relationship y=cx as an example, where y is the second count value, x is the first count value, and c is a constant. The first case is that before the data signal 10'' is transmitted (that is, the signal synchronization phase T1), the value of c is set to 1/3, for example. Therefore, at time t21 in FIG. 3A and the initial first count value is defined as a value of 48, the initial second count value is calculated as a value of 16. In the second case, the value of c is set to 1 when the data signal 10'’ is being transmitted (that is, the data transmission stage T2). That is, the second count value is equal to the first count value. Furthermore, during the transmission period of the data signal 10'', the second count value can be directly defined according to the corresponding first count value, and then the second count value is stored in the register 13. Taking the unit interval UI” as an example, at time t31, the potential of the sampling point 100 changes from a low potential VGL to a high potential VGH, and the count value of the first counter 11 is 20, so it corresponds to the first unit interval UI” The second count value is calculated to be 20.

In particular, this embodiment can still ensure that the data of the data signal 10" can be read within the data reading range even when the sampling frequency is shifted. The data reading method of the present disclosure further includes a self-calibration The program includes the following steps: when the potential of the sampling points 100 counted in the data reading range is changed from the first potential to the second potential or from the second potential to the first potential, comparing Corresponding to the count value of the first counter 11 and the second counter 12 at the sampling point 100 of the potential transition; if the count value of the second counter 12 at the sampling point 100 of the potential transition is greater than one-half of the first counter 11 If the count value of the sampling point 100 of the potential transition is increased, the count number of the second counter 12 is increased; and if the count value of the second counter at the sampling point 100 of the potential transition is less than one-half of the first counter 11 at the potential The number of counts at the sampling point of the transition is reduced by the number of counts of the second counter 12; among them, half of the number of counts of the first counter 11 at the sampling point 100 of the potential transition and the second counter 12 at the potential The difference between the count value of the sample point 100 of the transition is increased or decreased by the second counter 12.

Here, in this embodiment, the unit interval UI’’’ is taken as an example to describe the self-calibration procedure described above. Please refer to FIG. 3B again. At time t32, the potential of the sampling point 100 changes from a high potential VGH to a low potential VGL, the count count value of the second counter 12 is 10, and the count count value of the first counter 11 is 18. In other words, at time t32, the count value of the second counter 12 (value 10) is greater than one-half of the count value of the first counter 11 (value 9). Therefore, the self-calibration procedure of this embodiment will increase the count times of the second counter 12. Furthermore, this embodiment will increase or decrease the value of the second counter 12 according to the difference between the first half of the count value of the first counter 11 and the count value of the second counter 12 as the offset. Count the number of times. For example, at time t32, one-half of the count value of the first counter 11 is 9 and the count value of the second counter 12 is 10, so the difference between the two is 1. Furthermore, since the count value of the second counter 12 is greater than one-half of the count value of the first counter 11, and the difference between the two is 1, the self-calibration procedure of this embodiment will change the original second counter The count of 12 increases by 1. That is, the count value of the second counter 12 will increase from the original value 18 to the value 19. In this way, after the self-calibration process of this embodiment, the sampling point 100 of the potential transition can be effectively located in the central area of the unit interval, thereby ensuring that the data of the data signal 10" can be maintained within the data reading range To be read.

In addition, in this embodiment, the first counter 11 and the second counter 12 are reset back to 0 to perform subsequent counting operations. In other preferred embodiments, the first counter 11 and the second counter 12 do not need to be reset to 0, but continue to perform subsequent counting operations in a cumulative counting manner. That is, the present disclosure does not limit the counting methods of the first counter 11 and the second counter 12 herein.

FIG. 7 shows a block diagram of a data reading device according to an embodiment of the present disclosure. The data reading device 5 of the present disclosure is used to read data of a digital signal 10 having a first frequency, wherein the digital signal includes a synchronization signal and a data signal. The data reading device 5 includes, for example, a first counter 11 , The register 13, the oscillator 14 and the control unit 15. Among them, the first counter 11, the register 13 and the oscillator 14 are, for example, coupled to the control unit 15. In this embodiment, the data reading device 5 reads the data of the digital signal 10 through a communication interface, such as a display port (DisplayPort) interface.

As shown in FIG. 7, the oscillator 14 is used to generate a second frequency, wherein the second frequency is greater than the first frequency. In an embodiment, the second frequency is n times the first frequency, and n is an integer greater than one. In one embodiment, the first frequency is 1 MHz, and the second frequency is between 12 MHz and 16 MHz.

The first counter 11 is used to count the sampling points to obtain a first count value. The register 13 is used to store the number of sampling points. The control unit 15 is configured to execute: perform an over-sampling operation on the digital signal at the second frequency, and calculate a plurality of sampling points according to the over-sampling operation; correspondingly define a second count based on the first count value The frequency value; the over-sampling operation of the second counting frequency value on the data signal at the second frequency is a unit interval; within the unit interval, a data reading range is defined; and within the data reading range When the potential of the counted sampling points changes from a first potential to a second potential, it is determined that the data signal corresponding to the unit interval is a first value. When the potentials of the counted sampling points When changing from the second potential to the first potential, it is determined that the data corresponding to the unit interval of the data signal is a second value, wherein the first potential is different from the second potential, and the first value is different from The second value.

Furthermore, the control unit 15 is further configured to perform: when the potential of the sampling points counted in the data reading range is changed from the first potential to the second potential or from the second potential to the first potential , Record the count value of the sampling point at the potential transition, and define it as the first count value, and order the count value of the first counter to reset back to 0.

Furthermore, the control unit 15 is further configured to perform: perform the over-sampling operation on the synchronization signal to obtain the first count value before the data signal is transmitted; when the potential of the counted sampling points is determined by the first When the potential changes to the second potential, record the count value corresponding to the sampling point of the potential transition, and order the count value of the first counter to reset back to 0 and re-count; and when the re-counted sampling points When the potential changes from the first potential to the second potential again, it is determined whether the count value corresponding to the sampling point of the current potential transition is twice or more than the count value recorded in the previous record; The count value of the second record is defined as the first count value, and the count value of the first counter is instructed to reset back to 0, and then the data signal is transmitted.

Furthermore, the control unit 15 is further configured to perform: when the potentials of the sampling points that are counted while transmitting the data signal change from the first potential to the second potential, determine which sampling points correspond to the current potential transition Whether the count value is twice or more than the count value of the previous record; if so, end the transmission of the data signal.

Furthermore, the control unit 15 is further configured to perform: correspondingly define the count value of the first counter corresponding to the sampling point of the potential transition within the data reading range as the second count value; and temporarily store The device 13 stores the second count value.

As shown in FIG. 7, the data reading device 5 further includes a second counter 12 for counting the number of sampling points when the data signal is subjected to the oversampling operation. Among them, the second counter 12 is also coupled to the control unit 15, for example. In this embodiment, the control unit 15 is further configured to execute: perform the oversampling operation on the data signal according to the second count value within the unit interval, and when the unit interval ends, command the second counter Reset back to 0; define the count times i to j of the second counter as the data reading range; among them, the count times i is calculated by a formula: i = (m÷4) + k, and the count times j is calculated by A calculation formula: j = i + (m÷2) calculated, where m is the second count value; when the remainder of m÷4 is 0 to 2, k is 0; when the remainder of m÷4 is At 3 o'clock, k is 1.

Furthermore, the control unit 15 is further used to perform: when the potential of the sampling points counted in the data reading range is changed from the first potential to the second potential or from the second potential to the first potential Compare the corresponding count value of the first counter and the second counter at the sampling point of the potential transition; if the count value of the second counter at the sampling point of the potential transition is greater than one-half of the first If the count value of a counter at the sampling point of the potential transition is increased, the count number of the second counter is increased; and if the count value of the second counter at the sampling point of the potential transition is less than half of the first The count value of the counter at the sampling point of the potential transition is reduced by the count number of the second counter; wherein, according to one-half of the number of counts of the first counter at the sampling point of the potential transition and the second The counter increases or decreases the count number of the second counter by the difference of the count value of the sampling point at the potential transition.

In other embodiments, the second frequency may preferably be selected between 12 MHz and 16 MHz, but it is not limited to this.

In summary, the present disclosure mainly uses an over-sampling method to synchronize a digital signal and accurately capture data. Furthermore, the present disclosure only uses an oscillator, and does not need to use a phase locked loop. Therefore, cost and power consumption can be effectively reduced.

Although the present disclosure has been disclosed in the above with preferred embodiments, it is not intended to limit the present disclosure. Those with ordinary knowledge in the technical field of the present disclosure can make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of this disclosure shall be subject to those defined by the attached patent application scope.

1: Sending device 2: receiving device 3: Display interface interface 5: Data reading device 10: Digital signal 10’: Sync signal 10’’: Data signal 11: The first counter 12: second counter 13: register 14: Oscillator 15: control unit 21: Clock signal 30: main link 31: auxiliary channel 32: Hot plug detection signal line 100: sampling point 101: Synchronization end signal S10, S11, S12, S13, S14, S15, S16, S110, S111, S112, S150, S151: steps

Figure 1 shows a conventional system architecture diagram of the DisplayPort interface.

FIG. 2A shows a timing diagram of a digital signal of the present disclosure.

FIG. 2B shows an enlarged timing diagram of the data signal in FIG. 2A according to the present disclosure.

3A shows a schematic diagram of a digital signal of the method for reading data according to the present disclosure.

FIG. 3B is an enlarged view of the data signal in FIG. 3A of the present disclosure.

FIG. 4 shows a flowchart of a method of reading data according to the present disclosure.

FIG. 5A shows a sub-flow chart of step S15 in FIG. 4 according to the present disclosure.

FIG. 5B illustrates the data reading range corresponding to different unit intervals of the present disclosure.

FIG. 6 shows a flowchart of the synchronization signal performing the oversampling operation according to the present disclosure.

FIG. 7 is a block diagram of a data reading device according to an embodiment of the present disclosure.

3: Display interface interface

5: Data reading device

10: Digital signal

11: The first counter

12: second counter

13: register

14: Ring oscillator

15: control unit

Claims (10)

A data reading device for reading a digital signal with a first frequency, wherein the digital signal includes a synchronization signal and a data signal, and the data reading device includes: An oscillator for generating a second frequency, wherein the second frequency is greater than the first frequency; A first counter for counting multiple sampling points to obtain a first count value; and A control unit is used to execute: Performing an over-sampling operation on the digital signal at the second frequency, and calculating the sampling points according to the over-sampling operation; Correspondingly define a second count value based on the first count value; Performing the oversampling operation of the second count value on the data signal at the second frequency as a unit interval; Define a data reading range within the unit interval; and Within the data reading range, when the potential of the counted sampling points changes from a first potential to a second potential, it is determined that the data signal corresponding to the unit interval is a first value. When counting When the potential of the sampling points changes from the second potential to the first potential, it is determined that the data signal corresponding to the unit interval is a second value, where the first potential is different from the second potential, And the first value is different from the second value. The data reading device described in item 1 of the scope of patent application, wherein the control unit is further used to execute: when the potential of the sampling points counted in the data reading range is changed from the first potential to the second potential Or when changing from the second potential to the first potential, record the count value of the sampling point of the potential transition and define it as the first count value, and order the count value of the first counter to reset back to 0. For the data reading device described in item 1 of the scope of patent application, the control unit is further used to execute: Perform the over-sampling operation on the synchronization signal to obtain the first count value before the data signal is transmitted; When the potential of the counted sampling points changes from the first potential to the second potential, record the count value corresponding to the sampling point of the potential transition, and instruct the count value of the first counter to reset back to 0, and Recount; and When the potentials of the re-counted sampling points change from the first potential to the second potential again, determine whether the count value corresponding to the sampling point of the current potential transition is twice the count value recorded in the previous record Or more than twice; If yes, define the count value of this record as the first count value, and instruct the count value of the first counter to reset back to 0, and then perform the transmission of the data signal. For the data reading device described in item 3 of the scope of patent application, the control unit is further used to execute: When the data signal is transmitted and the potential of the counted sampling points is changed from the first potential to the second potential, it is determined whether the count value corresponding to the sampling point of the current potential transition is the count value of the previous record Twice or more than twice; If yes, end the transmission of the data signal. For example, the data reading device described in item 1 of the scope of patent application further includes a register, and the control unit is further used to execute: Correspondingly define the count value of the first counter corresponding to the sampling point of the potential transition in the data reading range as the second count value; and Make the register store the second count value. For example, the data reading device described in item 1 of the scope of patent application further includes a second counter. The data signal is counted during the over-sampling operation according to the second count value, and the control unit is further in the unit Perform the over-sampling operation on the data signal according to the second count value in the interval, and when the unit interval ends, command the second counter to reset back to 0. For the data reading device described in item 6 of the scope of patent application, the control unit is further used to execute: define the count times i to j of the second counter as the data reading range; wherein the count times i is calculated by a Formula: i = (m÷4) + k is calculated, the count number j is calculated by a calculation formula: j = i + (m÷2), where m is the second count value; when m÷4 When the remainder is 0 to 2, k is 0; when the remainder of m÷4 is 3, k is 1. For the data reading device described in item 6 of the scope of patent application, the control unit is further used to execute: When the potentials of the sampling points counted in the data reading range change from the first potential to the second potential or from the second potential to the first potential, compare the corresponding first counter with the The count value of the second counter at the sampling point of the potential transition; If the count value of the second counter at the sampling point of the potential transition is greater than one-half of the count value of the first counter at the sampling point of the potential transition, increase the count of the second counter; and If the count value of the second counter at the sampling point of the potential transition is less than one-half of the count value of the first counter at the sampling point of the potential transition, then the count of the second counter is reduced; Wherein, the second counter is increased or decreased according to the difference between one-half of the count value of the first counter at the sampling point at the potential transition and the second counter at the sampling point of the potential transition. The count of the counter. In the data reading device described in item 1 of the scope of patent application, there is a functional relationship between the first count value and the second count value. According to the data reading device described in claim 1, wherein the second frequency is n times the first frequency, and n is an integer greater than 1.

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