JPH0630501B2 - Bus transfer control method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bus transfer control system, and more particularly to data transfer between a plurality of data transmitters / receivers using two kinds of transfer buses, a data transfer bus and a status transfer bus. The present invention relates to a bus transfer control method when performing communication.

[Conventional technology]

As a method for connecting a plurality of data transmitting / receiving devices via a common bus and exchanging data via the common bus, the following methods are conventionally known.

Status of whether or not the receiving side device is in a data receivable state via the common bus when a plurality of data transmitting / receiving devices are connected by one kind of common bus and the transmitting side device acquires the right to use the common bus The method of verifying, and if possible, data transfer via the common bus.

A status transfer bus in which a plurality of data transmitters / receivers are connected by two kinds of transfer buses, a data transfer bus and a status transfer bus, and the sender device has acquired the right to use for vacancy and blockage of the data reception buffer memory of the receiver device. Via the data transfer bus to obtain the right to use the data transfer bus and transfer the data via the data transfer bus.
In the closed state, for example, a method of repeating the above verification process after waiting for a predetermined time.

[Problems to be solved by the invention]

However, in the above-described conventional method, since data transfer and status verification are performed on the same bus, while data transfer is being performed between any one of the data transmitting / receiving devices, the status between the other data transmitting / receiving devices is However, there is a drawback in that the status verification waiting time for the verification cannot be performed.

On the other hand, in the conventional method, since the transfer bus is duplicated in the data transfer bus and the status transfer bus,
The waiting time for status verification is reduced compared to the conventional method, but even if the right to use the status transfer bus is acquired, if there is no free space in the data reception bus of the receiving side device, no processing is performed and the status transfer will be performed again later. It has the drawback of having to acquire the right to use the bus and repeat verification.
Therefore, there is a problem that the usage rate of the status transfer bus increases and that data cannot be transferred promptly when the receiving side device has a vacancy in the data receiving buffer memory.

The present invention solves the drawbacks of the above conventional methods,
Its purpose is to reduce the utilization of the status transfer bus,
In addition, it is to enable the receiving side device to promptly transfer data when the data receiving buffer memory becomes vacant.

[Means for solving problems]

In order to achieve the above object, the present invention provides a plurality of data transmission / reception devices, a data transfer bus and a status transfer bus interconnecting the plurality of data transmission / reception devices, and a request for using the data transfer bus and the status transfer bus. In a bus transfer control system in a data communication system including a contention arbitration circuit for data transfer bus and a contention arbitration circuit for status transfer bus, the data transmission / reception device transmits data to another data transmission / reception device. The data transmission / reception device on the transmission side sets the transmission data in the transmission data buffer memory in its own data transmission / reception device, and then acquires the right to use the status transfer bus by the contention arbitration circuit for the status transfer bus. To the data transmitter / receiver on the receiving side via the And data transfer request control information including position information is released to release the right to use the status transfer bus, and the data transmitter / receiver on the receiving side that has received the data transfer request control information is the reception data buffer in its own data transmitter / receiver. At the time when there is free space in the memory and reception is possible,
A right to use the data transfer bus is acquired by the contention arbitration circuit for the data transfer bus, and a transmission data buffer memory in the data transmitter / receiver on the transmitting side is acquired according to the data transfer request control information received via the data transfer bus. The set transmission data addressed to itself is transferred to the reception data buffer memory.

[Action]

When the data transmission / reception device on the transmission side acquires the status transfer bus, it notifies the data transmission / reception device on the reception side of data transfer request control information including the amount of transmission data set in its own transmission data buffer memory and position information, The right to use the status transfer bus is handed over without verifying the free / closed status of the receive data buffer memory in the data transmitter / receiver on the receiving side. The above verification is left to the data transmitting / receiving device on the receiving side, and when the data transmitting / receiving device on the receiving side determines that the data can be received, the right to use the data transfer bus is acquired and the transmission set in the transmission data buffer memory is sent. The data is received in its own reception data buffer memory via the data transfer bus according to the notified data transfer request control information.

〔Example〕

 Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an example of a data communication system for carrying out the present invention.
And a data transfer bus 1 connected to each data transmission / reception device 10, n0, and a contention arbitration circuit 2 for this data transfer bus 1.
And a status transfer bus 3 connected to each data transmission / reception device 10, n0, and a contention arbitration circuit 4 for the status transfer bus 3.

Each data transmission / reception device 10, n0 includes a data transmission / reception control unit 13, n3.
And a transmission data buffer memory 11, n1 and a reception data buffer memory 12, n2, and a data transmission / reception control unit 13, n3
The transmission data buffer memories 11, n1 and the transmission data buffer memory write signal lines 131, n31 and the transmission data buffer memory read instruction signal lines 180, n80 are used for the reception data buffer memories 12, n2 and the reception data buffer memory read signal lines 132. , n32 and reception data buffer memory write instruction signal lines 170, n70, respectively, and the transmission data buffer memories 11, n1 and the data transfer bus 1 are connected by data transmission signal lines 111, n11, and the reception data buffer memory 12, n2 and the data transfer bus 1 are the data reception signal line 12
Connected with 1, n21. In addition, the data transmission / reception control unit 13,
n3 is a data transfer end reporting line 140, n4 on the data transfer bus 1.
0, data transfer end instruction lines 141, n41, address signal line 150,
It is connected by n50 and read instruction signal lines 160, n60, and is connected to the status transfer bus 3 by status instruction lines 133, n33 and status read lines 134, n34.

The contention arbitration circuit 2 for the data transfer bus is the data transfer bus 1
The data transmission / reception control unit 1
3, n3 are connected to data transfer bus use request lines 137, n37 and data transfer bus use permission lines 138, n38. The status transfer bus contention arbitration circuit 4 arbitrates the right to use the status transfer bus 3 independently of the data transfer bus contention arbitration circuit 2.
Are connected to the status transfer bus use request lines 135 and n35 and the status transfer bus use permission lines 136 and n36.

Hereinafter, the operation of the present embodiment will be described by taking as an example the case of communicating data from the data transmitting / receiving apparatus 10 to the data transmitting / receiving apparatus n0. FIG. 2 is a flow chart showing an example of a transmission process performed by the data transmission / reception control unit 13 of the data transmission / reception device 10 at that time, and FIG. 3 is a flow chart showing an example of a reception process performed by the data transmission / reception control unit n3. When a data transmission request is generated in a certain data transmission / reception device 10, the data transmission / reception control unit 13 writes the transmission data to the transmission data buffer memory 11 via the transmission data buffer memory write signal line 131 as shown in FIG. (S
1) Next, the status transfer bus use request line 135 is activated (hereinafter referred to as ON) to make a status transfer bus use request (S2).

When the status transfer bus contention arbitration circuit 4 receives a status transfer bus use request from the data transmitter / receiver 10,
This request is arbitrated between the status transfer bus use request from another data transmission / reception device, and the bus use permission is given to the highest priority one. Now, assuming that the data transmission / reception device 10 is permitted to use, the status transfer bus contention arbitration circuit 4 turns on the status transfer bus use permission line 136.
Then, the data transmission / reception device 10 is permitted to use the status transfer bus 3.

When it is determined in step S3 that the use permission is given, the data transmission / reception control unit 13 of the data transmission / reception device 10 determines the number of bytes of the transmission data set in the transmission data buffer memory 11, buffer address information, and if necessary, its own device. The data transfer bus request control information including the identification information is sent to the status indication line 133 (S4). This data transfer request control information is transmitted to the data transmission / reception control unit n3 of the data transmission / reception device n0 via the status transfer bus 3 and the status read line n34. Data transmission / reception control unit 13 that has sent data transfer request control information using the status transfer bus
After that, the status transfer bus use request line 135 is made inactive (hereinafter referred to as OFF) (S5) to yield the status transfer bus use right.

On the other hand, the data transmitter / receiver n0, which has received the data transfer request control information, monitors the free state of its own receive data buffer memory n2 (S10), as shown in FIG. At this time, if reception is not possible, the data transfer bus use request line n37 is turned on to request use of the data transfer bus 1 at the time of the receivable state (S11).

The data transfer bus contention arbitration circuit 2 is a data transmission / reception device.
When a data transfer bus use request is received from n0, this request is arbitrated between the data transfer bus use request from another data transmitting / receiving device, and the bus use permission is given to the highest priority one. Now, assuming that the data transmission / reception device n0 is given permission to use the data transfer bus 1, the data transfer bus contention arbitration circuit 2 turns on the data transfer bus use permission line n38 to cause the data transmission / reception device n0 to perform data transfer bus 1 Give permission to use.

With the use permission, the data transmission / reception device n0 can communicate with the data transmission / reception device 10 using the data transfer bus 1. Therefore, after confirming that the data transmission control unit n3 of the data transmission / reception device n0 has issued the use permission ( S12), data transmitter / receiver 1
According to the number of data bytes and buffer address information reported in the data transfer request control information from 0, the data reception signal line n21, the data transfer bus 1 and the data transmission signal line 1
The transmission data addressed to itself in the transmission data buffer memory 11 is transferred to the reception data buffer memory n2 via 21 (S
13).

Various methods can be adopted as the above transfer method,
For example, it is performed as follows. First, the data transmission / reception control unit n3 transmits to the data transmission / reception control unit 13 the start address of the self-addressed transmission data in the transmission data buffer memory 11 which is previously notified via the address signal line n50, the data transfer bus 1, and the address signal line 150. Then, the first read instruction is given to the data transmission / reception control unit 13 via the read instruction signal line n60, the data transfer bus 1, and the read instruction signal line 160. When the address is given through the address signal line 150 and the first read instruction is applied, the data transmission / reception control unit 13 sends the data at the address in the transmission data buffer memory 11 to the transmission data buffer read instruction signal line 180.
Is read out in accordance with an instruction and is sent to the reception data buffer memory n2 via the data transmission signal line 111, the data transfer bus 1, and the data reception signal line n21. The data transmission / reception control unit 13
When the reception data buffer memory write instruction signal line n70 is used to store the transferred data in the reception data buffer memory n2 in synchronization with the read instruction transmission timing, and when the reception of one data is completed, the read instruction signal line n60
Give the lead instruction again. Upon receiving the read instruction, the data transmission / reception control unit 13 updates the read address of the transmission data buffer memory 11 and sends the next data to the data transmission signal line 111, the data transfer bus 1, the data reception signal line n.
It is sent to the reception data buffer memory n2 via 21. When such operation is repeated and the data transmission / reception control unit 13 completes the reception of the data of the reported number of bytes, the data transfer end report line n40 is turned on (S14), and this report line n40 is displayed. By turning on the signal line and the data transfer end line 141 of the connected data transfer bus 1 to notify the data transmission / reception control unit 13 of the end of the data transfer, and turning off the data transfer bus use request line n37 (S15). , Yields the right to use the data transfer bus 1.

〔The invention's effect〕

As described above, according to the present invention, when the data transmission / reception device on the transmission side acquires the right to use the status transfer bus,
The data transfer request control information including the amount of transmission data set in the transmission data buffer memory of the own data transmission / reception device and the address information is notified to the data transmission / reception device on the reception side via the status transfer bus, and the data transmission / reception device on the reception side , The data transmission buffer memory in the data transmission / reception device on the transmission side is acquired through the acquisition of the right to use the data transfer bus when the reception data buffer memory of its own becomes available for reception. Since the transmission data set to is fetched according to the previously notified data transfer request control information, the right to use the status transfer bus at the time of transmission can be acquired only once. There is an effect that the rate can be reduced. In addition, the receiving side is responsible for verifying its own received data buffer memory, and when the receiving side becomes ready to receive the data already prepared, the effect that prompt data communication is possible There is also.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a data communication system embodying the present invention, FIG. 2 is a flow chart of an example of processing at the time of transmission of a data transmission / reception control unit, and FIG. 3 is an example of processing at the time of reception of a data transmission / reception control unit. It is a flow chart. In the figure, 1 ... Data transfer bus, 2 ... Contention arbitration circuit for data transfer bus, 3 ... Status transfer bus, 4 ...
… Competitive arbitration circuit for status transfer bus, 10, n0 …… Data transceiver, 11, n1 …… Transmit data buffer memory, 1
2, n2 …… Reception data buffer memory, 13, n3 …… Data transmission / reception control unit, 111, n11 …… Data transmission signal line, 121, n21
...... Data reception signal line, 131, n31 …… Transmission data buffer memory write signal line, 132, n32 …… Reception data buffer memory read signal line, 133, n33 …… Status indication line, 134, n34 …… Status read line , 135, n35 …… Status transfer bus use request line, 136, n36 …… Status transfer bus use permission line, 137, n37 …… Data transfer bus use request line, 138, n38 …… Data transfer bus use permission line, 140 , n40
...... Data transfer end report line, 141, n41 ...... Data transfer end instruction line, 150, n50 ...... Address signal line, 160, n60 ...... Read instruction signal line, 170, n70 ...... Reception data buffer memory write instruction signal Line, 180, n80 ... Transmission data buffer memory read instruction signal line.

Claims (1)

[Claims] 1. A plurality of data transmission / reception devices, a data transfer bus and a status transfer bus interconnecting the plurality of data transmission / reception devices, and a data transfer for arbitrating use requests of the data transfer bus and the status transfer bus. In a bus transfer control system in a data communication system including a bus contention arbitration circuit and a status transfer bus contention arbitration circuit, when a data transceiver transmits data to another data transceiver, the data transceiver on the transmitting side After setting the transmission data in the transmission data buffer memory in its own data transmitter / receiver, the status transfer bus contention arbitration circuit acquires the right to use the status transfer bus, and the receiving side of the status transfer bus receives the right to use the status transfer bus. The data transmission / reception device stores the data including the set amount of transmission data and position information. Data transfer request control information is released to release the right to use the status transfer bus, and the data transmitting / receiving device on the receiving side that has received the data transfer request control information has a vacant receive data buffer memory in its own data transmitting / receiving device. When it becomes ready to receive,
A right to use the data transfer bus is acquired by the contention arbitration circuit for the data transfer bus, and a transmission data buffer memory in the data transmitter / receiver on the transmitting side is acquired according to the data transfer request control information received via the data transfer bus. A bus transfer control method characterized in that the set transmission data addressed to itself is transferred to the reception data buffer memory.