JP2505792B2 - Micro computer system - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention operates a plurality of microcomputers in synchronism with each other, collates the contents of a data bus of each microcomputer with a collating circuit, and collates the contents when the contents do not match. Regarding a bus-synchronized microcomputer system that stops output, direct data transfer between a memory and an external input / output circuit. memory. Access (DirectMemo
ryAccess. Hereinafter referred to as "DMA". ) Circuit temporarily stops the microcomputer and the matching circuit, and directly exchanges data between the external input / output circuit and the memory, then reads the contents of the memory by the microcomputer and inputs it to the matching circuit. By collating, the speed of data exchange with the external input / output circuit can be increased with a simple circuit configuration.

2. Description of the Related Art A microcomputer system of this type is known as this type of microcomputer system. In the figure, 1 and 2 are microcomputers, 3 is a matching circuit,
Reference numerals 4 and 5 are external input / output circuits.

The collation circuit 3 collates the contents of the data buses A and B of the microcomputers 1 and 2, generates a collation output when the contents of the data buses A and B match, and stops the collation output when they do not match. Let Microcomputer 1, 2
Data is transmitted and received between the external input / output circuits 4 and 5 via the data buses A and B.

Problems to be Solved by the Invention However, in the case of the conventional example shown in FIG. 2, data transmission / reception is simultaneously performed between the data buses A and B and the external input / output circuits 4 and 5 while operating the collation circuit 3. Since the configuration is performed, when high-speed processing is required for data exchange with the external input / output circuits 4 and 5, a synchronization signal generation circuit is required, which complicates the circuit configuration and ensures synchronization. In addition, there is a problem that the processing time becomes slow and it is disadvantageous for high speed processing.

Means for Solving Problems In order to solve the above-mentioned conventional problems, the present invention operates a plurality of microcomputers in synchronization and causes the contents of a data bus of each microcomputer to be collated by a collation circuit. In the microcomputer system that stops the collation output when there is a mismatch, the DAM circuit temporarily suspends the microcomputer and the collation circuit at the time of data transfer between the memory and the external input / output circuit, and the data bus Data is directly exchanged between the external input / output circuit and the memory through
After that, the contents of the memory are read out by the microcomputer and input to the matching circuit for matching.

In the microcomputer system according to the present invention, the DMA circuit temporarily stops the microcomputer and the matching circuit when data is exchanged between the memory and the external input / output circuit, and the external input / output circuit and the memory are connected through the data bus. Directly exchange data with.
Since the collation circuit is stopped during DMA, a synchronization signal creation circuit etc. is not required, and the circuit configuration is simple and
The processing time for synchronization is not necessary, and the demand for high-speed processing can be sufficiently satisfied.

Then, after the data transfer between the external input / output circuit and the memory is completed, the contents of the memory are read out by the microcomputer and are input to the matching circuit for matching to determine whether the data contents match or mismatch.

First Embodiment FIG. 1 is a block diagram of a microcomputer system according to the present invention. In the figure, the same reference numerals as those in FIG. 2 denote the same components. 6 is a DMA circuit provided on the data bus A of the microcomputer 1;
Reference numeral 7 is a DMA circuit connected to the data bus B of the microcomputer 2, 8 is a memory connected to the data bus A of the microcomputer 1, and 9 is a memory connected to the data bus B of the microcomputer 2.

In a normal operation in which data is not exchanged with the external input / output circuits 4 and 5, the contents of the data buses A and B are collated by the collation circuit 3, and when the data contents of the data buses A and B are the same, A collation output is generated from the collation circuit 3, and if there is no coincidence, the collation output is stopped.

Next, when exchanging data with the external input / output circuits 4 and 5, signals a ₁₁ and a ₂₁ indicating that data is to be exchanged are input from the external input / output circuits 4 and 5 to the DMA circuits 6 and 7. DMA
When the circuits 6 and 7 receive the signals a ₁₁ and a ₂₁ , they give the microcomputers 1 and 2 the signals a ₁₂ and a ₂₂ for stopping their operations. Microcomputer 1, 2
Responds to the signals a ₁₂ and a _22, and sends signals a ₁₃ and a ₂₃ indicating that the data transmission / reception to / from the external input / output circuits 4 and 5 is permitted, to the DMA circuit 6,
At the same time as returning to 7, the operation of its own is stopped. At the same time that the microcomputers 1 and 2 stop operating, the matching circuit 3 also stops operating.

The DMA circuits 6 and 7 receive the signals a ₁₃ and a ₂₃ from the microcomputers 1 and 2, and then directly to the external input / output circuits 4 and 5 and the memories 8 and 9 between both 4-8 and 5-9. The signals a ₁₄ and a ₂₄ for giving and receiving data are given to the. As a result, through the data buses A and B, as shown by dotted lines b ₁ and b ₂ , between the external input / output circuit 4 and the memory 8 and the external input / output circuit 5
Data is directly exchanged between the memory 9 and the memory 9.
As a result, data exchange with the external input / output circuits 4 and 5 can be processed at high speed.

Then, after the data transfer is completed between the external input / output circuit 4 and the memory 8 and between the external input / output circuit 5 and the memory 9, the data transfer operation is completed from the DMA circuits 6 and 7 to the microcomputers 1 and 2. Give signals a ₁₅ and a ₂₅ . The microcomputers 1 and 2 read the contents of the memories 8 and 9 on the basis of the signals a ₁₅ and a ₂₅ and make the collation circuit 3 collate them to determine whether the data contents match or do not match.

As described above, according to the present invention, a plurality of microcomputers are operated in synchronization, the contents of the data buses of the respective microcomputers are collated by the collation circuit, and collation output is stopped when the contents do not coincide. In the microcomputer system, when data is exchanged between the memory and the external input / output circuit, the DMA circuit temporarily stops the microcomputer and the matching circuit, and the external input / output circuit and the memory are connected through the data bus. Externally input / output circuit with a simple circuit configuration, since data is directly exchanged between them, and thereafter the contents of the memory are read by the microcomputer and input to the verification circuit for verification. To provide a microcomputer system capable of speeding up data exchange with it can.

[Brief description of drawings]

FIG. 1 is a block diagram of a microcomputer system according to the present invention, and FIG. 2 is a block diagram of a conventional microcomputer system. 1, 2 ... Microcomputer 3 ... Collation circuit 4, 5 ... External input / output circuit 6, 7 ... DMA circuit 8, 9 ... Memory

Claims (1)

(57) [Claims] 1. A microcomputer system in which a plurality of microcomputers are operated in synchronization and the contents of a data bus of each microcomputer are collated by a collation circuit, when data is exchanged between a memory and an external input / output circuit, direct. memory. The access circuit temporarily stops the micro computer and the collation circuit, and directly exchanges data between the external input / output circuit and the memory through the data bus, and then the microcomputer stores the data in the memory. A microcomputer system, wherein contents are read out and input into the matching circuit for matching.