JP2003150538A - Data transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transfer data to one common bus while avoiding competition without stopping data transfer from output devices when the data outputted from a plurality of output devices compete with each other. SOLUTION: Holding means 4a and 4b hold the data from the output devices 1a and 1b. A selecting means 5 transfer the data to the bus 16 by selecting one of the respective data directly outputted from the output devices and the respective data outputted from the holding means. For example, when outputting the data from the output device 1b when transferring to the bus by selecting the data of the output device 1a, after finishing the data transfer from the output device 1a by holding the data from the output device 1b by the holding means 4b, the data held by the holding means 4b are selected, and transferred to the bus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transfer device which avoids contention of data output from a plurality of output devices and transfers the data to one common bus.

[0002]

2. Description of the Related Art As a conventional data transfer device, Japanese Unexamined Patent Publication No.
The one described in Japanese Patent Publication No. 185371 is known, and its configuration is shown in FIG. In this conventional data transfer device, external devices 301 and 302 are connected to a processor (CPU) 100 via a common bus, and a buffer 200 that stores data when the data conflicts from the external devices 301 and 302 is stored in the processor 100 and the external device. Provided between 301 and 302,
The buffer 2 is switched by the changeover switches 101 and 102.
00 is stored or transferred to the processor 100.

When data is transferred from the processor 100 to the external device 301 during data transfer from the external device 302 to the external device 301, the processor 100 switches the changeover switch 102 to the buffer 200 side, and the external device 302 causes the external device 301 to move. Data to be transferred to the processor 100 and the external device 301 after the data is temporarily stored.
Data transfer to. After the data transfer to the processor 100 and the external device 301 is completed, the data held in the buffer 200 is transferred to the external device 301 via the processor 100.
By transferring to, data conflict is avoided.

[0004]

However, in the conventional data transfer device, when contention occurs, data output from another external device is stopped while holding data from the external device. However, there is a problem that the competition of data transferred in real time cannot be avoided because the data output from the external device cannot be stopped.
Further, there is a problem that throughput is reduced because data output from the external device is stopped.

The present invention has been made in order to solve the conventional problem. When the data output from a plurality of output devices conflict, the conflict is avoided without stopping the data transfer from the output devices. It is an object of the present invention to provide a data transfer device capable of transferring to one bus.

[0006]

SUMMARY OF THE INVENTION The present invention is a data transfer device for avoiding contention of data output from a plurality of output devices and transferring the data to one common bus. A plurality of holding means for respectively holding respective data to be stored, each of the data directly output from the plurality of output devices, and one of the data output from the plurality of holding means are selected and transferred to the bus. If a data conflict occurs during selection of the data output directly from the selection means and one of the plurality of output devices, the holding means holds the data after the selection means has finished transferring the selected data. Control means for controlling so as to select the competitive data held in the means. With this configuration, it is possible to avoid data conflict without stopping data output from a plurality of output devices, and to transfer data to a transfer destination by a common bus without loss of data.

The present invention is also a data transfer device for avoiding contention of data output from a plurality of output devices and transferring the data to one common bus, wherein each data output from the plurality of output devices is transferred. When data conflicts occur during transfer to the bus by selecting data that is directly output from one of the plurality of holding units and one of the plurality of output devices, transfer of the selected data ends. Selection means for selecting contention data held in the holding means later and transferring it to the bus. With this configuration, it is possible to avoid data conflict without stopping data output from a plurality of output devices, and to transfer data to the transfer destination by the common bus without loss of data. The number and mounting area can be reduced.

The present invention is also a data transfer device which avoids contention of data output from a plurality of output devices and transfers the data to one common bus, wherein the plurality of output devices include:
Holding means for holding data output from an output device having a low priority, each data directly output from the plurality of output devices, and one of the data output from the holding means are selected and transferred to the bus. Selecting means and the data output directly from the low-priority output device is selected, when the data conflict occurs, the selecting means selects from among the plurality of output devices the high-priority output device. Control means for directly selecting the output data, and controlling so as to select the data of the low-priority output device held in the holding means after the transfer of the data of the high-priority output device is completed,
It is characterized by having. With this configuration, it is possible to avoid data conflict without stopping data output from a plurality of output devices, and to transfer data to a transfer destination by a common bus without loss of data, and When data having a high priority and data having a low priority compete with each other, the data having a high priority can be preferentially transferred.

The present invention is also a data transfer device which avoids contention of data output from a plurality of output devices and transfers the data to one common bus.
When holding means for holding data output from an output device having a low priority and data directly output from the output device having a low priority are selected and data conflict occurs during transfer to the bus, Of the plurality of output devices, the data directly output from the high priority output device is selected and transferred to the bus, and the holding unit is provided after the transfer of the data directly output from the high priority output device is completed. And selecting means for selecting the data of the low-priority output device held in step 1 and transferring it to the bus. With this configuration, it is possible to avoid data conflict without stopping data output from a plurality of output devices, and to transfer data to a transfer destination by a common bus without loss of data, and When data having a high priority and data having a low priority compete with each other, the data having a high priority can be preferentially transferred, and the number of components and the mounting area can be further reduced.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> In FIG. 1, output devices 1a and 1a are provided.
b is control means 3 via control lines 10a and 10b, respectively.
Connected to. The output data from the output devices 1a and 1b are input to the selection means 5 through the data lines 11a and 11b, respectively, and the data lines 110a and 11b, respectively.
It is also input to the holding means 4a and 4b through 0b. The holding means 4a and 4b respectively include the control means 3 to the control line 12
It is controlled through a and 12b.

When the data is held in the holding means 4a and 4b, the holding means 4a and 4b respectively control lines 13a and 13b.
b is asserted to notify the control means 3 that the data is held in the holding means 4a, 4b. Holding means 4a,
The data of 4b is applied to the selecting means 5 through the data lines 14a and 14b, respectively. The selection means 5 is connected to the control means 3 by a control line 15, and transfers any one of the data lines 11a, 11b, 14a, 14b by a control signal sent from the control means 3 through the control line 15. It is selected whether or not it is transferred to the bus 16. The holding means 4a, 4b may be composed of flip-flops or FIFO type memories.

The operation of the data transfer device configured as described above will be described with reference to FIG. First, a case where there is no data competition between the output devices 1a and 1b will be described. The output device 1a asserts the control line 10a before outputting data, and continues asserting until the last data output starts. The control means 3 includes control lines 10a, 10b, 13a, 1
From the state of 3b, a control signal is output to the selecting means 5 through the control line 15. In this case, only the output device 1a transfers the data, and the holding means 4a, 4b does not hold the data, so only the control line 10a is asserted and the other control lines 10b, 13a, 13b are negated. .

Therefore, the control means 3 judges that there is no competing data, and transmits the control signal using the control line 15 so that the selection means 5 selects the data on the data line 11a and transfers it to the bus 16. The selection means 5 uses the control signal transmitted from the control means 3 through the control line 15 to select the data line 11a.
By selecting the above data and transferring it to the bus 16, the data output from the output device 1 a is transferred to the bus 16.

The same can be done when transferring only the data of the output device 1b. The output device 1b asserts the data line 10b before outputting data, and continues asserting until the last data output starts. Control means 3
Is asserted only on the control line 10b and the other control lines 10a,
From the state that 13a and 13b are negated, it is judged that there is no conflicting data, and the control line 15 is so selected as to select the data on the control line 11b and transfer it to the bus 16.
To send a control signal. The selection means 5 is the control means 3
The data output from the output device 1b is transferred to the bus 16 by selecting the data on the data line 11b from the control signal transmitted via the control line 15 from the bus 16 and transferring the selected data to the bus 16.
Transferred to.

Next, a case where data is output from the output device 1b while the data is being output from the output device 1a and contention occurs will be described with reference to FIG. 1 and FIG. 2 which is a timing chart. First, the output device 1a uses the data a
The control line 10a is asserted immediately before the output of 1, a2 to a6 (timing 1t in FIG. 2). In the control means 3, only the control line 10a is asserted and the other control lines 10a are
Since b, 13a, and 13b are negated, a control signal is transmitted to the selection means 5 so as to select the data on the data line 11a and transfer it to the bus 16. As a result, the output device 1
The data a1 and a2 of a are transferred to the bus 16.

After that, the output device 1b outputs the data b1, b2.
2 is output, the control line 10b is asserted at the timing 2t in FIG. 2 to start the data output, and the control means 3 holds the data in the holding means 4b.
The holding means 4b is controlled by using b. The holding unit 4b holds the data b1 and b2 of the data line 110b, and asserts the control line 13b at timing 3t in FIG. 2 to notify the control unit 3 that the data is held. Holding means 4
b keeps asserting the control line 13b while holding the data. The output data a3 of the output device 1a
a6 is continuously transferred to the bus 16.

When the data output (data a1 to a6 in FIG. 2) is completed, the output device 1a negates the control line 10a, whereby only the control line 13b is asserted (timing 4t in FIG. 2). . Since the control line 13b is asserted, the control means 3 recognizes that data is present in the holding means 4b, and the selection means 5 is selected.
Then, the data b1 and b2 held in the holding means 4b are selected and transferred. The selecting means 5 selects the data on the data line 14b which is the output of the holding means 4b and transfers it to the bus 16. When the holding means 4b starts the transfer of the last held data b2, it negates the control line 13b at timing 5t in FIG. 2 to complete the data transfer.

According to the first embodiment of the present invention as described above, even if the data from the other is output during the data output of the output device 1a or 1b, the data output later will be the holding means 4a. Alternatively, the data held in 4b is output, and after one of the data is transferred, the data held in the holding means 4a or 4b is output. As described above, it is possible to avoid the data conflict without stopping the data output from the plurality of output devices 1a and 1b, and to transfer the data to the transfer destination by one bus 16 without losing the data. become. In the above example, the output devices are 1a, 1
Although the case where the number of b is two has been described, it is needless to say that even when the number of output devices is three or more, a method similar to the above, in which a holding unit corresponding to the output device is added, can be implemented.

<Second Embodiment> Further, the function of the control means 3 is included in the selection means 5, and the control lines 10a, 10b, 13 are provided.
a, 13b are connected to the selection means 5 and control lines 12a, 12
The second embodiment of the present invention can be realized by outputting b from the selection means 5 and deleting the control means 3 and the control line 15. According to the second embodiment, since the control means 3 and the control line 15 can be deleted, it is possible to reduce the number of parts and the mounting area.

<Third Embodiment> Next, a third embodiment of the present invention will be described.
FIG. 3 shows a data transfer device according to this embodiment. 3 shows a case where the data of the output device 1a has a higher priority than the data of the output device 1b. In the first embodiment of FIG. 1, the holding means 4a and the data line 14a, the control line 12a of the holding means 4a, 13a has been deleted.

The operation of the data transfer device configured as described above will be described with reference to FIG. 3 and FIG. 4 which is a timing chart. When the output device 1b asserts the control line 10b at the timing 10t in FIG. 4 before outputting the data b10, the control means 3 controls the selection means 5 to select the data on the data line 11b and transfer it to the bus 16. A signal is transmitted, and as a result, the data b10 and b12 of the output device 1b are transferred to the bus 16.

Here, consider a case where the output device 1a asserts the control line 10a and outputs the data a10 to a13. When the control line 10a is asserted at the timing 11t in FIG. 4, the control unit 3 controls the holding unit 4b to hold the data b12 to b14 of the output unit 1b by the control line 12b. At the same time, the control line 15 to the selecting means 5
The control signal is transmitted to select and transfer the data a10 to a13 on the data line 11a. The selection means 5 is shown in FIG.
The data a of the data line 11a at the timing 12t in
10 to a13 are selected and transferred. When the holding means 4b holds the data b12 to b14 of the output means 1b, it asserts the control line 13b at the timing 13t in FIG.
The control means 3 is notified that the data is held.

As described above, when the data of the output device 1a is input after the data b10 and b11 are transferred, the output device 1a
The data a is prioritized and the data a10 to a13 are selected and transferred to the bus 16. The data b1 output from the output device 1b during the output of the data a10 to a13
2 to b14 are held by the holding means 4b. When the output device 1a transfers all the data at the timing 14t in FIG. 4, the control lines 10a, 10b, 13a, 13b.
Of these, only the control line 13b is asserted. The control means 3 controls the control lines 10a, 10b, 13a, 13
From the state of b, it is judged that the data is held in the holding means 4b, the selection means 5 selects the data (data b12 to b14) held in the holding means 4b, and the bus 16 is selected.
Control to transfer to. The holding means 4b negates the control line 13b when the transfer of the last held data is started at the timing 15t in FIG. 4, and the data transfer is ended.

As described above, according to the third embodiment of the present invention, when the data from the output device 1a having a high priority is output, the data having a low priority is held in the holding means 4b. After the transfer of the high priority data is completed, the low priority data held in the holding means 4b is transferred. Therefore, high priority data can be transferred without waiting, and low priority data can be transferred to the common bus 16 without loss.

<Fourth Embodiment> The function of the control means 3 shown in FIG. 3 is included in the selection means 5, and the control lines 10a, 10
The fourth embodiment of the present invention can be realized by inputting b and 13b to the selecting means 5, outputting the control line 12b from the selecting means 5, and deleting the selecting means 3 and the control line 15. According to the fourth embodiment, since the selection unit 3 and the control line 15 can be deleted, it is possible to reduce the number of parts and the mounting area.

<Fifth Embodiment> Next, a data transfer apparatus according to a fifth embodiment of the present invention will be described. In the fifth embodiment, the control means 3 in the third embodiment of FIG.
It is realized by configuring with a state machine. FIG. 5 shows a state transition diagram of the state machine. State 5 in FIG.
1 (INIT) indicates that no data is transferred to the bus 16. The state 52 (A) indicates that the control signal for transferring the data of the output device 1a is transmitted to the selecting means 5, and the state 53 (B) transmits the control signal for transferring the data of the output device 1b to the selecting means 5. And state 5
4 (Buffer B) indicates that the control signal for transferring the data of the holding means 4b is transmitted to the selecting means 5.

The next state is determined by the control lines 11a, 11b and 13b and the current state. For example, if the current state is the state 52 (A) and the control line 11a is negated,
When b is asserted, the next state 53 (B) is entered, and the control means 3 sends a control signal for transferring the data of the output device 1b to the selection means 5. In the above example, the data of the output device 1a is prioritized. However, if other data is prioritized, it goes without saying that it can be implemented by changing the state and transition condition of the state machine.

As described above, according to the fifth embodiment of the present invention, when changing the priority of data to be transferred, it can be realized by changing the state of the state machine and the transition condition. It enables flexible system configuration.

<Sixth Embodiment> In the above example, the control means 3 is constituted by a state machine. However, the selection means 5 of the second or fourth embodiment of the present invention can be used. It goes without saying that the sixth embodiment of the present invention configured by a state machine can also be realized in the same manner as above.

<Seventh Embodiment> A block diagram of a seventh embodiment of the present invention is shown in FIG. 6, and a timing chart is shown in FIG. In the seventh embodiment of the present invention, the decoding means 6 and the AND gate 7 are added to the first embodiment, the control line 15 is input to the decoding means 6, and the decoding means 6 is connected to the AND gate 7. The output 17 and the transfer timing signal 18 are input, and the output of the AND gate 7 is used as the data transfer timing signal 19. The output 17 of the decoding means 6 is determined by the state of the control line 15 which is the output of the control means 3. The control means 3 uses the control line 11
When a control signal is transmitted to the selecting means 5 to transfer data to any of a, 11b, 14a and 14b, the output 17 of the decoding means 6 outputs "High", and otherwise outputs "Low". I will.

The transfer timing signal 18 is a reference signal used for transfer and may be a clock signal. The transfer timing signal 18 and the output 17 of the decoding means 6 are ANDed to generate a data transfer timing signal 19. As shown in the timing chart of FIG. 7, the data transfer timing signal 19 thus generated outputs the transfer timing signal 18 when there is data to be transferred, that is, when the output of the decoding means 6 is “High”. , Outputs “Low” when there is no data to transfer.

As described above, according to the seventh embodiment of the present invention, the timing signal for transferring the data can be generated during the data transfer, and the timing signal can be directly output without the instruction of the CPU. It becomes possible to write the transfer data first.

<Eighth Embodiment> In the above description, the case where the timing signal 19 is output from the control means 3 has been described, but the eighth embodiment of the present invention configured to output the timing signal 19 from the selection means 5 is described. It goes without saying that the embodiment can be similarly realized by configuring the control line 15 to be output from the selection device 5 and applying the above method to the second embodiment of the present invention.

<Ninth Embodiment> Next, according to the ninth embodiment of the present invention in which the data transfer device of the present invention is implemented by a semiconductor integrated circuit, data competition from a plurality of circuits is avoided. Since the data can be transferred by one bus, the area of the semiconductor integrated circuit can be reduced and the current consumption can be reduced.

<Tenth Embodiment> According to the tenth embodiment of the present invention in which the data transfer device of the present invention is applied to a digital signal processing system, data is often transferred in real time. In the digital signal processing system, a plurality of data can be transferred by one bus without stopping the data transfer, so that the mounting area can be reduced. Needless to say, the same effect can be obtained when applied to an image processing system such as a mobile communication system, a DVD player, or a car navigation system.

<Eleventh Embodiment> Furthermore, according to the eleventh embodiment of the present invention in which the data transfer device of the present invention is provided in a mobile terminal, data transfer between a plurality of devices is performed by one bus. Since it can be performed, it is possible to reduce the mounting area which is a problem in the mobile terminal. The mobile terminal may be a mobile information terminal such as a mobile phone, a mobile music player, or a mobile computer.

<Twelfth Embodiment> Next, a twelfth embodiment of the present invention in which a computer system is equipped with the data transfer apparatus of the present invention will be described. Bus 1 in Figure 1
If the connection destination of 6 is a CPU and the output devices 1a and 1b are external devices such as an external memory and an external disk storage device, data transfer to the CPU becomes possible without stopping data transfer from a plurality of external devices. Since the data transfer from the external device cannot be stopped, it is possible to suppress the system performance deterioration. In addition, bus 1
The connection destination of 6 may be a microcomputer or DSP,
The external device may be a digital device such as a DVD recording / reproducing device or a mobile phone.

[0038]

As described above, according to the first aspect of the present invention, data conflicts can be avoided without stopping data output from a plurality of output devices, and data can be shared without loss. It becomes possible to transfer data to the transfer destination by the bus. According to the invention of claim 2,
It is possible to avoid data conflicts without stopping data output from multiple output devices, and to transfer data to a transfer destination by a common bus without loss of data. The area can be reduced. According to the third aspect of the present invention, data competition is avoided without stopping data output from a plurality of output devices, and data is transferred to a transfer destination by a common bus without loss of data. Further, when the data of high priority and the data of low priority conflict, the data of high priority can be preferentially transferred. According to the invention described in claim 4, the data conflict is avoided without stopping the data output from the plurality of output devices, and the data is transferred to the transfer destination by the common bus without losing the data. In addition, when high-priority data and low-priority data compete with each other, high-priority data can be preferentially transferred, and the number of components and mounting area can be further reduced. .

[Brief description of drawings]

FIG. 1 is a block diagram of a data transfer device according to a first embodiment of the present invention.

FIG. 2 is a timing chart for explaining the data transfer device according to the first embodiment of the present invention.

FIG. 3 is a block diagram of a data transfer device according to a third embodiment of the present invention.

FIG. 4 is a timing chart for explaining a data transfer device according to a third embodiment of the present invention.

FIG. 5 is a state transition diagram of control means of a data transfer device according to a fifth embodiment of the present invention.

FIG. 6 is a block diagram of a data transfer device according to a seventh embodiment of the present invention.

FIG. 7 is a timing chart of a data transfer device according to a seventh embodiment of the present invention.

FIG. 8 is a block diagram of a data transfer device in the related art.

[Explanation of symbols]

1a, 1b output device 3 control means 4a, 4b holding means 5 means of selection 6 Decoding means 7 AND GATE

Claims (4)

[Claims] 1. A data transfer device that avoids contention of data output from a plurality of output devices and transfers the data to one common bus, and holds each data output from the plurality of output devices. A plurality of holding means, a selection means for selecting one of the data directly output from the plurality of output devices and one of the data output from the plurality of holding means, and transferring the selected data to the bus; If the data conflict occurs while selecting the data directly output from the one of the plurality of output devices, the selecting unit sets the conflict data held in the holding unit after the transfer of the selected data is completed. A data transfer device comprising: a control unit that controls to select. 2. A data transfer device that avoids contention of data output from a plurality of output devices and transfers the data to one common bus, and holds each data output from the plurality of output devices. When data conflicts occur during transfer to the bus by selecting the data directly output from the plurality of holding units and one of the plurality of output devices, the holding is performed after the transfer of the selected data ends. Selecting means for selecting the competitive data held in the means and transferring it to the bus. 3. A data transfer device for avoiding contention of data output from a plurality of output devices and transferring the data to one common bus, wherein the output device having a lower priority among the plurality of output devices. Holding means for holding data to be output; selecting means for selecting one of the data directly output from the plurality of output devices and one of the data output from the holding means and transferring the selected data to the bus; When a data conflict occurs while selecting the data directly output from the low priority output device, the selection means selects the data directly output from the high priority output device among the plurality of output devices. A data transfer device comprising: a control unit that controls the selection of the data of the output device of low priority held in the holding unit after the transfer of the data of the output device of high priority is completed. 4. A data transfer device which avoids contention of data output from a plurality of output devices and transfers the data to one common bus, wherein the output device with the lowest priority among the plurality of output devices Holding means for holding the data to be output, and a plurality of output devices among the plurality of output devices when data conflict occurs during transfer to the bus by selecting data directly output from the low priority output device , The data directly output from the high-priority output device is selected and transferred to the bus, and the low-priority data held in the holding unit after the transfer of the data directly output from the high-priority output device is completed. A data transfer device comprising: a selection unit that selects data from an output device and transfers the data to the bus.