Data transfer device

Abstract

A data transfer device according to one aspect of the present disclosure comprises: a data transmission unit that has a transmission port; and a data reception group that includes n (n ≥ 2) reception units of the first reception unit to the n-th reception unit. The transmission port of the data transmission unit is configured to serially transmit data to be captured by each of the n reception units. The i-th reception unit (2 ≤ i ≤ n-1) has an input port and a data port. The input port of the i-th reception unit receives data from the data port of the (i-1)-th reception unit, and the data port of the i-th reception unit transmits data except for data to be received only by the i-th reception unit from the data received by the input port of the i-th reception unit.

Description

Data transfer device

[0001] The present disclosure relates to a data transfer device.

[0002] In recent years, high-resolution displays such as 4K and 8K have come into practical use. Because such displays have a large number of pixels, sending signals directly to each pixel independently would require an extremely large number of wires between the display and the semiconductor chip that controls the image.

[0003] For this reason, efforts have been made to reduce the number of wirings, such as by standardizing the clock signal that transfers data for each pixel (see Japanese Patent Application Laid-Open No. 2011-128535) or by serializing the data to reduce the number of data signals (see Japanese Patent Application Laid-Open No. 8-10166).

[0004] JP 2011-128535 A JP 8-10166 A

[0005] Even if a clock signal is shared, the number of signals that can be reduced is limited, so data serialization is generally used alone or in combination to reduce the number of data signals. For example, if data on four signal lines is serialized and the data transfer speed is to be maintained, the data must be transferred at four times the frequency. Such high-speed data transfers tend to consume significantly more power.

[0006] The present disclosure has been made in light of the above-mentioned circumstances, and an object of the present disclosure is to provide a data transfer device that reduces the number of data signals while suppressing an increase in power consumption.

[0007] A data transfer device according to one aspect of the present disclosure includes one data transmission unit having a transmission port, and a data reception group having n reception units from a first reception unit to an nth reception unit (n≧2), wherein the transmission port of the data transmission unit is configured to serially transmit data captured by each of the n reception units, the first reception unit has an input port and a data port, the input port of the first reception unit receives data from the transmission port of the data transmission unit, and the data port of the first reception unit selects data received by only the first reception unit from the data received by the input port of the first reception unit. The i-th receiver (2≦i≦n−1) has an input port and a data port, the input port of the i-th receiver receives data from the data port of the (i−1)th receiver, and the data port of the i-th receiver is configured to transmit data received by the input port of the i-th receiver excluding data that should be received only by the i-th receiver; the n-th receiver has an input port, and the input port of the n-th receiver is configured to receive data from the data port of the (n−1)th receiver.

[0008] The data transfer device of the present disclosure can reduce the number of data signals while suppressing an increase in power consumption.

[0009] Fig. 1 is a block diagram showing a module configuration of a data transfer device according to one aspect of the present disclosure. Fig. 2 is a block diagram showing a data exchange relationship between the receiving unit of Fig. 1. Fig. 3 is an example of a timing chart of the data exchange in Fig. 2. Fig. 4 is a block diagram showing a configuration of an automatic discrimination mechanism of the receiving unit of Fig. 1. Fig. 5 is a block diagram showing an example configuration of a data transfer system using the data transfer device of Fig. 1.

[0010] [Description of an embodiment of the present disclosure] (1) A data transfer device according to one aspect of the present disclosure includes one data transmission unit having a transmission port, and a data reception group having n reception units from a first reception unit to an nth reception unit (n≧2), wherein the transmission port of the data transmission unit is configured to serially transmit data captured by each of the n reception units, the first reception unit has an input port and a data port, the input port of the first reception unit receives data from the transmission port of the data transmission unit, and the data port of the first reception unit receives only data received by the input port of the first reception unit. The i-th receiver (2≦i≦n−1) has an input port and a data port, the input port of the i-th receiver receives data from the data port of the (i−1)th receiver, and the data port of the i-th receiver is configured to transmit data received by the input port of the i-th receiver excluding data that should be received only by the i-th receiver, and the n-th receiver has an input port, and the input port of the n-th receiver is configured to receive data from the data port of the (n−1)th receiver.

[0011] This data transfer device serially outputs data to be transmitted from the transmitting port to n receiving units, thereby reducing the number of data signals between the data transmitting unit and the data receiving group. Furthermore, in this data transfer device, the data port of the i-th receiving unit transmits data that is the data received by the input port of the i-th receiving unit, excluding data that should only be received by the i-th receiving unit. Therefore, compared to a case where the data is not excluded, the signal change at the data port of the i-th receiving unit can be reduced more than the signal change at the input port of the i-th receiving unit, thereby preventing an increase in power consumption. Here, "data that should only be received by the i-th receiving unit" refers to data received by the i-th receiving unit that does not need to be transmitted to the (i+1)-th receiving unit.

[0012] (2) In the data transfer device of (1), data transmission from the transmitting port is preferably performed at a constant data rate, and the data rate of data transmission at the data port of the jth receiving unit (1≦j≦n−1) is lower than the data rate of data reception at the input port of the jth receiving unit. By reducing the data rate of data reception at the data port of the jth receiving unit in this manner, power consumption due to data signal changes can be reduced. Here, "data rate" refers to the number of bits of data transmitted and received per unit time (e.g., 1 second).

[0013] (3) In the data transfer device of (2) above, the data lengths of the data captured by each of the n receiving units may be configured to be equal, and the data transmission rate of the data port of the jth receiving unit may be (n-j) / n times the data rate of the data transmission rate of the transmitting port. By configuring the data transmission rate of the data port of the jth receiving unit in this manner, it is possible to stably acquire data while reducing power consumption. Here, "data captured" (by a receiving unit) is synonymous with data received only by the corresponding receiving unit.

[0014] (4) In the data transfer device according to any one of (1) to (3), the data of the transmission port may be data received by the n receiving units, arranged in descending order of the number i of the receiving units. This configuration makes it easier to align the timing of the data received by the n receiving units.

[0015] (5) In the data transfer device of any one of (1) to (4) above, the n receiving units may have an automatic discrimination mechanism capable of recognizing their own number i. By having the n receiving units have an automatic discrimination mechanism capable of recognizing their own number i in this way, initial setup can be easily performed.

[0016] (6) In the data transfer device of (5), the automatic discrimination mechanism may have a transfer start signal indicating the start of transfer to itself, a number input signal indicating the number i of the receiving unit to receive, a number register that holds the number input signal when the transfer start signal 41 indicates the start of transfer, a transfer output signal indicating the start of transfer to the next stage, and a number output signal indicating the number (i+1) of the receiving unit to be received by the next stage, and may be controlled so that the transfer output signal indicates the start of transfer after receiving the transfer start signal. By configuring the automatic discrimination mechanism in this way, a stable communication state can be ensured early, especially in systems that perform high-speed communication.

[0017] [Details of the embodiment of the present disclosure] A data transfer device according to an embodiment of the present disclosure will be described below.

[0018] 1 includes one data transmission unit 10 and a data reception group 20. The data transmission unit 1 can be configured with a circuit such as an LSI, for example.

[0019] <Data Transmitting Unit> The data transmitting unit 10 has three input ports 11 and one transmitting port 12 .

[0020] The three input ports 11 receive data to be received by three receiving units 30, which will be described later.

[0021] The data transmitter 10 is configured to serially transmit the data received by each of the three receivers 30 from the transmitter port 12. Specifically, the input data input from the three input ports 11 is converted from parallel to serial and transmitted from the transmitter port 12. In this case, to prevent a decrease in the data transfer rate, it is preferable that the data rate of the transmitter port 12 is 3p, where p is the data rate of the input data. In other words, the frequency of data transfer is multiplied.

[0022] In particular, when the data rate is high (the data transfer frequency is high), it is advisable to use a CDR (Clock Data Recovery) method for transferring data, in which a clock, which is a reference for data transfer, is further incorporated into the data signal. The data transfer device 1 can be suitably used for CDR signal transfer.

[0023] Here, since circuits for performing parallel-serial conversion, multiplication of data transfer frequency, and signal conversion to the CDR system are well known, detailed explanations thereof will be omitted.

[0024] <Data Receiving Group> The data receiving group 20 has three receiving units 30 (a first receiving unit 31, a second receiving unit 32, and a third receiving unit 33). Each of the three receiving units 30 has an input port 34, a data port 35, and an output port 36.

[0025] 2, the input port 34 of the first receiving unit 31 is configured to receive data from the transmitting port 12 of the data transmitting unit 10, and the data port 35 of the first receiving unit 31 is configured to transmit data obtained by excluding only the data to be received by the first receiving unit 31 from the data received by the input port 34 of the first receiving unit 31. The data to be received by the first receiving unit 31 is output to the output port 36 of the first receiving unit 31.

[0026] The input port 34 of the second receiving unit 32 receives data from the data port 35 of the first receiving unit 31, and the data port 35 of the second receiving unit 32 is configured to transmit data obtained by excluding only the data to be received by the second receiving unit 32 from the data received by the input port 34 of the second receiving unit 32. The data to be received by the second receiving unit 32 is output to the output port 36 of the second receiving unit 32.

[0027] The input port 34 of the third receiving unit 33 is configured to receive data from the data port 35 of the second receiving unit 32. The data to be received by the third receiving unit 33 is output to the output port 36 of the third receiving unit 33.

[0028] Here, the data processing of the data receiving group 20 will be described in detail.

[0029] As described above, the data from the transmission port 12 of the data transmitter 10 (data from the transmission port 12) received by the input port 34 of the first receiver 31 is serialized data taken in by each of the three receivers 30 (the first receiver 31, the second receiver 32, and the third receiver 33). The data taken in by each of the three receivers 30 may be 1 bit or multiple bits.

[0030] The data of the transmitting port 12 may contain an identifier indicating which receiving unit 30 should receive the data. In this case, each receiving unit 30 can determine which data to receive based on this identifier.

[0031] Alternatively, the data in the transmitting port 12 may be arranged in a predetermined order. In this case, each receiving unit 30 can determine which data to receive based on the data's position in the order. This method eliminates the need to add an identifier, allowing for efficient data transfer. In this case, the data received by each of the three receiving units 30 may be arranged in descending order of the receiving unit 30 number i.

[0032] Furthermore, it is preferable that data transmission from the transmitting port 12 be performed at a constant data rate, and that the data lengths of the data taken in by each of the three receiving units 30 be configured to be equal. Below, as shown in R1-IN (DR3) in Figure 3, the data rate of data transmission from the transmitting port 12 is constant at P (period T = 1 / P), the data length of each receiving unit 30 is 3 bits, and the data is arranged in descending order of number i (data from the third receiving unit 33, data from the second receiving unit 32, and data from the first receiving unit 31), but this does not mean that the data of the transmitting port 12 of the data transfer device 1 is limited to these conditions.

[0033] In the data transfer device 1, the data rate of data transmission at the data port 35 of the jth receiver (1≦j≦2) is lower than the data rate of data reception at the input port 34 of the jth receiver. By reducing the data rate of data reception at the data port 35 of the jth receiver in this way, it is possible to reduce power consumption due to changes in the data signal. Furthermore, if the data transfer device 1 is configured as a circuit, it is possible to design a smaller circuit area for the receiver with a lower data rate, which in turn allows for lower costs for the data transfer device 1.

[0034] In particular, when n receivers 30 are provided, it is preferable that the data port 35 of the jth receiver transmits data at a rate (n-j) / n times the data rate P of the data transmission of the transmit port 12. Configuring the data transmission of the data port 35 of the jth receiver in this manner reduces power consumption while stably acquiring data. In the data transfer device 1 shown in FIG. 1, n=3, so as shown in FIG. 3, the data rate at the data port 35 of the first receiver 31 (j=1) is 2 / 3P (=(3-1) / 3×P; cycle is 1.5T), and the data rate at the data port 35 of the second receiver 32 (j=2) is 1 / 3P (=(3-2) / 3×P; cycle is 3T). For example, if the data rate of data transmission at the transmitting port 12 is 4.5 Gbps, the data rate at the data port 35 of the first receiving unit 31 is 3.0 Gbps, and the data rate at the data port 35 of the second receiving unit 32 (j=2) is 1.5 Gbps. Below, we will continue the explanation using an example where this data rate relationship exists.

[0035] In general, the data transfer period determined by the data rate may be subject to fluctuations in the period due to delays or jitter, making transfers between different data rates unstable. To ensure stable transfers between different data rates, it is recommended to leave a margin of 20% or less for a data rate that is (n-j) / n times the data rate. Specifically, it is recommended to set the data rate to be (n-j) / n times or more and (n-j) / n times x 1.2 or less for a data rate that is (n-j) / n times the data rate.

[0036] As described above, the input port 34 of the first receiving unit 31 receives the data shown as R1-IN in Fig. 3 in synchronization with the period T. Note that in Fig. 3, the parentheses for each signal indicate a label indicating the data rate, with DR3 being a data group of 4.5 Gbps (period T), DR2 being 3.0 Gbps (period 1.5T), and DR1 being 1.5 Gbps (period 3T).

[0037] The first receiver 31 outputs data R1-OUT to be received by the first receiver 31 from R1-IN to the output port 36 of the first receiver 31. This R1-OUT can be performed in synchronization with the 3T period of DR1. Data #1 of R1-IN to be received by the first receiver 31 is received in the last three periods. Therefore, as shown in FIG. 3, R1-OUT is output in synchronization with the 3T period of DR1 after data #1 has been received.

[0038] Furthermore, the first receiving unit 31 transmits data R1-D, which is data R1-IN received by the input port 34 of the first receiving unit 31 but which is to be received only by the first receiving unit 31, to the data port 35. This R1-D is output in synchronization with the 1.5T period of DR2. Because the data of R1-IN that is to be transmitted to the data port 35 is data for the first six periods, R1-D is output in synchronization with the 1.5T period of DR2 immediately after the input port 34 of the first receiving unit 31 starts receiving.

[0039] Since the input port 34 of the second receiver 32 receives data from the data port 35 of the first receiver 31, R2-IN becomes the same signal as R1-D and is synchronized with the period 1.5T of DR2.

[0040] The second receiver 32 outputs data R2-OUT to be received by the second receiver 32 from R2-IN to the output port 36 of the second receiver 32. This R2-OUT can be generated in synchronization with the 3T period of DR1. Data #2 of R2-IN to be received by the second receiver 32 is received in the latter three periods. Therefore, as shown in FIG. 3, R2-OUT is output in synchronization with the 3T period of DR1 after data #2 has been received.

[0041] The second receiving unit 32 also transmits data R2-D, which is data R2-IN received by the input port 34 of the second receiving unit 32 but which is to be received by the second receiving unit 32, to the data port 35. This R2-D is output in synchronization with the 3T cycle of DR1. Because the data of R2-IN that is to be transmitted to the data port 35 is the data for the first three cycles, R2-D is output in synchronization with the 3T cycle of DR1 immediately after the input port 34 of the second receiving unit 32 starts receiving.

[0042] Since the input port 34 of the third receiver 33 receives data from the data port 35 of the second receiver 32, R3-IN becomes the same signal as R2-D and is synchronized with the period 3T of DR1.

[0043] At this stage, R3-IN contains only data to be received by the third receiver 33, so the R3-IN signal can be simply synchronized with the 3T period of DR1 and output as R3-OUT to the output port 36. In Fig. 3, the period can be adjusted so that the output is synchronized with the output ports 36 of the first receiver 31 and second receiver 32.

[0044] <Automatic Discrimination Mechanism> It is preferable that the three receiving units 30 have an automatic discrimination mechanism capable of recognizing their own number i. By having the three receiving units 30 have an automatic discrimination mechanism capable of recognizing their own number i in this way, initial setup can be easily performed.

[0045] For example, the automatic discrimination mechanism may be such that a ROM is provided in each receiving unit 30 and the number i is determined from data written to the ROM when the system is started, or such that the number i is given to a number recognition port provided in each receiving unit 30 when the system is started. However, particularly in the case of a CDR system that transfers data at high speed with an embedded clock, this processing may be difficult and the manufacturing costs of the LSI and the like including the data transfer device 1 may increase.

[0046] Furthermore, the above-described method may increase manufacturing costs. Specifically, for example, if a ROM is provided in each receiving unit 30, the area of ​​the receiving unit 30 may increase. Even if the ROM is mounted on a printed wiring board outside the receiving unit 30, the size of the printed wiring board increases. These increases in area lead to increased manufacturing costs. Furthermore, even if the external pins of the receiving unit 30 are fixed to assign the number i to a number recognition port provided in the receiving unit 30, a dedicated printed wiring board matching the pattern for fixing the number i must be provided, for example, which increases the manufacturing cost of the printed wiring board.

[0047] In contrast to this, when the CDR method is adopted, for example, as shown in Figure 4, the automatic discrimination mechanism 40 has a transfer start signal 41 that indicates the start of transfer to itself, a number input signal 42 that indicates the number i of the receiving unit 30 that should receive, a number register 43 that holds the number input signal 42 when the transfer start signal 41 indicates the start of transfer, a transfer output signal 44 that indicates the start of transfer to the next stage, and a number output signal 45 that indicates the number (i+1) of the receiving unit 30 that should receive at the next stage, and is controlled so that the transfer output signal 44 indicates the start of transfer after receiving the transfer start signal 41.

[0048] 4, in the initial state, the first receiving unit 31 outputs a transfer output signal 44 that is inactive, and a number output signal 45 that is the value of the number register 43 plus 1. In this state, the first receiving unit 31 receives from the outside that the transfer start signal 41 is active and that the number input signal 42 is 1. When received from the outside, the number input signal 42 is always 1. The transfer start signal 41 activates the automatic discrimination mechanism 40, and is active for only one period.

[0049] When the transfer start signal 41 becomes active, the first receiving unit 31 stores the value of the number input signal 42 in the number register 43. That is, the number register 43 becomes 1, and the number output signal 45 becomes 2 by adding 1 to the number input signal 42. After that, the transfer output signal 44 is made active for only one cycle.

[0050] The transfer start signal 41 of the second receiving unit 32 is connected to the transfer output signal 44 of the first receiving unit 31, and the number input signal 42 of the second receiving unit 32 is connected to the number output signal 45 of the first receiving unit 31. At this time, the second receiving unit 32 operates in the same manner as the first receiving unit 31, and upon receiving that the transfer output signal 44 of the first receiving unit 31 has become active, it stores 2 in the number register 43, sets its own number output signal 45 to 3, and activates the transfer output signal 44.

[0051] The third receiving unit 33 is configured in the same way, and the number register 43 thereof holds 3.

[0052] In this way, each receiving unit 30 can recognize its own number i. By configuring the automatic discrimination mechanism 40 in this way, it becomes possible to quickly ensure a stable communication state, especially in a system that performs high-speed communication. Furthermore, this automatic discrimination mechanism 40 makes it possible to make each receiving unit 30 have the same configuration, which also makes it possible to suppress manufacturing costs.

[0053] <Advantages> The data transfer device 1 serially outputs data to be transmitted from the transmission port 12 to the three reception units 30, thereby reducing the number of data signals between the data transmission unit 10 and the data reception group 20. Furthermore, in the data transfer device 1, the data port 35 of the ith reception unit 30 transmits data obtained by excluding data that should only be received by the ith reception unit 30 from the data received by the input port 34 of the ith reception unit 30. Therefore, compared to a case where the data is not excluded, the signal change at the data port 35 of the ith reception unit 30 can be reduced more than the signal change at the input port 34 of the ith reception unit 30, thereby preventing an increase in power consumption.

[0054] [Other Embodiments] The above-described embodiments do not limit the configuration of the present disclosure. Therefore, the above-described embodiments may include omissions, substitutions, or additions of components based on the description in this specification and common general technical knowledge, and all of these should be construed as belonging to the scope of the present disclosure.

[0055] In the above embodiment, the receiving group has three receiving units, but the number of receiving units is not limited to three and may be two or four or more. When the number of receiving units is n (n≧2), the n receiving units have input ports and data ports, and a data transmitting unit is configured to serially transmit data captured by each of the n receiving units from the transmitting port, the input port of the first receiving unit receives data from the transmitting port, and the data port of the first receiving unit is configured to transmit data obtained by excluding data that should be received only by the first receiving unit from the data received by the input port of the first receiving unit, the input port of the i-th receiving unit (2≦i≦n−1) receives data from the data port of the (i−1)th receiving unit, and the data port of the i-th receiving unit is configured to transmit data obtained by excluding data that should be received only by the i-th receiving unit from the data received by the input port of the i-th receiving unit, and the input port of the n-th receiving unit is configured to receive data from the data port of the (n−1)th receiving unit.

[0056] The number of receivers is preferably between 3 and 8. If the number of receivers is less than the lower limit, the number of data signals between the transmitter and the receiver group may not be sufficiently reduced. Conversely, if the number of receivers exceeds the upper limit, the data transfer period between the transmitter and the receiver group may become too short, making stable communication difficult.

[0057] In the above embodiment, the third receiver, which is the final stage of the three receivers, has a data port, but the final stage data port can be omitted. On the other hand, if the third receiver has a data port, each receiver can have the same configuration, which has the advantage of making it easier to design and expand the data transfer device disclosed herein.

[0058] In the above embodiment, the case where three receiving units each have an output port was described, but the output ports are not essential components, and the present disclosure also intends to provide a data transfer device in which some or all of the output ports are omitted.

[0059] In the above embodiment, the number of input ports of the transmitter is the same as the number of receivers. However, the number of input ports of the transmitter and the number of receivers do not necessarily have to be the same and may be different. For example, the number of input ports of the transmitter may be four and the number of receivers may be three. In this case, when data is input to each input port of the transmitter at a data rate D1 and output from the transmission port of the transmitter at a data rate D2, the data rate can be determined so that, for example, D1 × 4 = D2 holds.

[0060] The data transfer device can be used in parallel. That is, a data transfer system can be constructed that includes a plurality of the data transfer devices arranged in parallel. For example, as shown in Fig. 5, when a data transfer system 100 is constructed by arranging two data transfer devices 1 of Fig. 1 in parallel, six data can be transferred over two signal lines.

[0061] The data transfer device of the present disclosure can reduce the number of data signals while suppressing an increase in power consumption.

[0062] REFERENCE SIGNS LIST 1 Data transfer device 10 Data transmission unit 11 Input port 12 Transmission port 20 Data reception group 30 Reception unit 31 First reception unit 32 Second reception unit 33 Third reception unit 34 Input port 35 Data port 36 Output port 40 Automatic discrimination mechanism 41 Transfer start signal 42 Number input signal 43 Number register 44 Transfer output signal 45 Number output signal 100 Data transfer system

Claims

1. A data transmission unit having a transmission port; and a data reception group having n reception units from a first reception unit to an nth reception unit (n≧2), wherein the transmission port of the data transmission unit is configured to serially transmit data captured by each of the n reception units, the first reception unit has an input port and a data port, and the input port of the first reception unit is configured to receive data from the transmission port of the data transmission unit, and the data port of the first reception unit is configured to transmit data obtained by excluding only data to be received by the first reception unit from data received by the input port of the first reception unit, the ith reception unit (2≦i≦n-1) has an input port and a data port, and the input port of the ith reception unit is configured to receive data from the data port of the (i-1)th reception unit, and the data port of the ith reception unit is configured to transmit data obtained by excluding data to be received only by the ith reception unit from data received by the input port of the ith reception unit, A data transfer device wherein the nth receiving unit has an input port, and the input port of the nth receiving unit is configured to receive data from the data port of the (n-1)th receiving unit.

2. A data transfer device as described in claim 1, wherein data transmission from the transmitting port is performed at a constant data rate, and the data rate of data transmission at the data port of the jth receiving unit (1≦j≦n-1) is lower than the data rate of data reception at the input port of the jth receiving unit.

3. A data transfer device as described in claim 2, wherein the data lengths of the data taken in by each of the n receiving units are configured to be equal, and the data transmission rate of the data port of the jth receiving unit is (n-j) / n times the data rate of the data transmission rate of the transmitting port.

4. A data transfer device according to any one of claims 1 to 3, wherein the data at said transmission port is the data taken in by each of said n receiving units arranged in descending order of the number i of said receiving units.

5. A data transfer device according to any one of claims 1 to 3, wherein said n receiving units have an automatic discrimination mechanism capable of recognizing their own number i.

6. A data transfer device as described in claim 5, wherein the automatic discrimination mechanism has a transfer start signal indicating the start of transfer to itself, a number input signal indicating the number i of the receiving unit to receive, a number register which holds the number input signal when the transfer start signal indicates the start of transfer, a transfer output signal which indicates the start of transfer to the next stage, and a number output signal which indicates the number (i+1) of the receiving unit to receive at the next stage, and is controlled so that the transfer output signal indicates the start of transfer after receiving the transfer start signal.

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