JPH0553980A - Bus communication system - Google Patents

Abstract

PURPOSE:To facilitate state confirmation during communication, error analysis in the case of error and the test of a priority control circuit by holding priority control data in the case of bus transmission. CONSTITUTION:A bus transmitting request is held in a transmitting request register 1, the request of a high priority order is selected from those requests by a priority control part 2, and the result is held in an arbitration register 3. When the transmitting request is completed, the end of the request is held in an end information register 5, and the completed request is erased from the transmitting request register 1. In the case of generating error, a bus communication control part 4 holds the registers 1, 3 and 5. In the case of an arbitration test, the test of the priority control part 2 is executed by spuriously completing the request held in the arbitration register 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bus communication system,
In particular, it relates to a bus communication system having a function of holding arbitration information.

[0002]

2. Description of the Related Art The conventional bus communication system does not hold arbitration information and does not perform an arbitration test. Further, when an error occurs, error information is collected without holding the registers and the like after the error occurs.

[0003]

This conventional bus communication system has no arbitration information holding function,
It was difficult to test the arbitration itself. Also,
When the error occurred, it was difficult to analyze the error because the registers were not held.

An object of the present invention is to provide a bus communication system which facilitates the status confirmation during communication, the error analysis at the time of error, and the test of arbitration itself.

[0005]

According to the present invention, there is provided a transmission request register for holding information of a bus transmission request, a priority control circuit for selecting a bus transmission request having the highest priority among the information of the transmission request register, An arbitration register that holds a high-priority bus transmission request selected by the priority control circuit, transmission / reception information, and the like, and termination information that retains termination when the bus transmission request retained in the arbitration register is terminated. A register and a bus communication control circuit having a function of deleting the completed bus transmission request from the transmission request register.

Further, according to the present invention, the bus communication control circuit retains the information of the transmission request register, the arbitration register and the termination information register in the function of deleting the completed bus transmission request from the transmission request register. It is preferable to have a function.

Further, according to the present invention, by receiving the pseudo end signal without performing bus communication, the bus transmission request held in the arbitration register is pseudo ended and the priority control circuit is tested. It is desirable to have an arbitration test control circuit.

[0008]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the bus communication system of the present invention. The bus communication system of FIG. 1 includes a transmission request register 1, a priority control unit 2, an arbitration register 3, a bus communication control unit 4, an end information register 5 and an arbitration test control unit 6.

The transmission request register 1 holds the information of the bus transmission request, the priority control unit 2 selects the request having the highest priority among the transmission request registers 1, and the arbitration register 3 holds the result of the priority control unit 2. Then, the end information register 5 holds the end status of the bus transmission.

Next, the operation of this embodiment will be described.

When the bus transmission request is stored in the transmission request register 1, the priority control unit 2 selects the bus transmission request having the highest priority in the transmission request register 1 and holds it in the arbitration register 3.

The bus communication control unit 4 includes a transmission request register 1
When the bus transmission request is stored in, the bus communication control unit 4 outputs the bus transmission request signal 7 to the bus, and when the bus transmission request ends and the end report signal 8 is received from the bus,
The completion of the bus transmission request held in the arbitration register 3 is stored in the end information register 5, and the corresponding request in the transmission request register 1 is deleted.

When the bus communication control unit 4 receives the error signal 9 when an error occurs, the bus communication control unit 4 is
Information of the transmission request register 1, the arbitration register 3, and the end information register 5 is held at the time of error occurrence.

Further, during the arbitration test, a bus transmission request is set in the transmission request register 1, a bus transmission request having a high priority is held in the arbitration register 3, and the arbitration test control unit 6 receives the pseudo end signal 10. Then, the pseudo transmission such as write access to the arbitration register 3 is terminated, the bus transmission request retained in the arbitration register 3 is terminated in a pseudo manner, and the termination information register 5 retains the termination, and the transmission request register 1 The bus transmission request that has ended is deleted, and the arbitration register 3 holds the bus transmission request having the next highest priority. In this case, no transmission request is made to the bus.

As described above, according to the present embodiment, by holding the transmission request in the arbitration register, the state during communication can be confirmed, and at the time of error, the information at the time of error occurrence is secured in each register. The analysis is easy, and by providing the arbitration test control unit, the priority control unit can be easily tested.

[0017]

As described above, according to the present invention, since the register for holding the status of priority control is arranged, the status during communication can be confirmed. Moreover, when an error occurs, the error analysis is easy because the information at the time of the error is held.

Further, by disposing the register for holding the status of the priority control and the arbitration test control section, the test of the priority control section is facilitated, and the diagnostic performance and the test function can be greatly improved.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

[Explanation of symbols]

 1 Transmission request register 2 Priority control unit 3 Arbitration register 4 Bus communication control unit 5 End information register 6 Arbitration test control unit 7 Bus transmission request signal 8 End report signal 9 Error signal 10 Pseudo end signal

Claims (3)

[Claims] 1. A transmission request register for holding information of a bus transmission request, a priority control circuit for selecting a bus transmission request having the highest priority among the information of the transmission request register, and the priority control circuit. An arbitration register that holds a high-priority bus transmission request and transmission / reception information, an end information register that holds that the bus transmission request held in the arbitration register has ended, and an end bus transmission request And a bus communication control circuit having a function of deleting from the transmission request register. 2. The bus communication control circuit has a function of deleting the completed bus transmission request from the transmission request register, and a function of holding information of the transmission request register, the arbitration register and the termination information register when an error occurs. The bus communication method described in 1. 3. An arbitration test control circuit for testing a priority control circuit by artificially ending a bus transmission request held in an arbitration register by receiving a pseudo end signal without performing bus communication. The bus communication system according to claim 1.