JPH02271449A - Bus fault detecting system - Google Patents

Abstract

PURPOSE:To prevent unnecessary bus holding at the time of the occurrence of bus fault and to improve the using efficiency of the bus by setting the monitoring time of a bus fault detecting timer to an optimum value at every equipment with which a data processor executes communication. CONSTITUTION:When a data processor 1 communicates with an equipment 4, the processor 1 sets the timer monitoring time for which the response speed of the equipment 4 is taken into consideration to a timer register 3a through the signal line 2c of a bus 2. When the processor 1 sends an order to the equipment 4, a bus fault detection timer 3b detects the address strobe signal of this order on the signal line 2b of the bus 2 to start the time monitor. When the equipment 4 is in fault, the address strobe signal of response information cannot be sent within the timer monitoring time set to the register 3a and the timer 3b overflows. The timer 3b detects the bus stack fault by this overflow and sends a bus error signal to the signal line 2a of the bus 2 to inform the processor 1 of this fault, and the output of the equipment in fault to the bus 2 is released.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bus fault detection method for a data processing system in which devices are connected via a bus.

[Conventional technology]

Conventionally, as a bus failure detection method for this type of data processing system, there is a method of monitoring the stack time on the bus control line. That is, a bus fault detection timer is provided to monitor the response time from other devices to communication from the data processing device, and if there is no response before this bus fault detection timer overflows, it is determined that a bus fault has occurred. .

[Problem to be solved by the invention]

In the conventional bus failure detection method described above, the value of the bus stack monitoring time of the bus failure detection timer is a fixed value ( For example, 150 μs), and if a -degree bus stuck occurs, the bus will not be released until the bus fault detection timer overflows, regardless of the cause of the bus stuck.

Therefore, even if a communication with a short bus holding time (for example, 1 μs) gets stuck, the bus fault detection timer counts unnecessary time, resulting in unnecessary bus holding.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bus failure detection method that does not hold the bus unnecessary when a bus failure occurs in a data processing system and can improve bus usage efficiency.

[Means to solve the problem]

The bus fault detection method of the present invention detects a fault in the bus in a data processing system in which a data processing device and a plurality of devices communicating with the data processing device are connected by a bus, by monitoring the stack time of communication between the devices. In the bus fault detection method carried out by the method, the data processing device sets a value of a monitoring time for bus fault detection in accordance with a response time of the communication destination device.

〔Example〕

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. The data processing system of this embodiment includes a data processing bag fil that performs data processing, and a data processing device 1 that communicates with each other to perform data input/output operations. A bus 2 that connects the devices, a timer register 3a that sets the value of the monitoring time, and a stack of the bus 2 that is 1 m long when specified by the timer register 3a. A bus fault detection circuit 3 having a bus fault detection timer 3b is provided.

The bus 2 also includes a signal line 2a for a bus error signal, a signal line 2b for an address strobe signal, and a signal 112c for other control signals, addresses, and data signals.

Next, the operation will be explained. When data processing device 1 communicates with device 4, data processing device 1 communicates with device 4 in advance.
A timer monitoring time that takes into account the response speed of is set in the timer register 3a via the signal line 2c of the bus 2. When the data processing device 1 sends an order to the device 4,
The bus fault detection timer 3b detects the address strobe signal of this order on the signal line 2b of the bus 2 and starts time monitoring.

If the device 4 is normal, it returns response information to the data processing device 1 within the timer monitoring time set in the timer register 3a. The bus failure detection timer 3b detects the address strobe signal in the response information signal 112b and ends time monitoring.

If the devices W and 4 are in failure, the address strobe signal of the response information cannot be sent out within the timer monitoring time set in the timer register 3a, and the bus failure detection timer 3b overflows. The bus fault detection timer 3b thereby detects a bus stack fault, and the signal line 2a of the bus 2
III′i! The output of device F to bus 2 is canceled.

〔Effect of the invention〕

As explained above, the bus fault detection method of the present invention sets the value of the monitoring time of the bus fault detection timer to the optimum value for each device with which the data processing device communicates, so that when a bus fault occurs, unnecessary This has the effect of eliminating the need for buses to be held and increasing the efficiency of bus usage.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. 1... Data processing device, 2... Bus, 2a+ 2
b. 2c... Signal line, 3... Bus fault detection circuit, 3a.
... Timer register, 3b... Bus failure detection timer, 4.5... Device.

Claims (1)

[Claims] In a bus failure detection method of a data processing system in which a data processing device and a plurality of devices communicating with the data processing device are connected by a bus, failure of the bus is detected by monitoring stack time of communication between the devices. A bus failure detection method characterized in that a data processing device sets a value of a monitoring time for bus failure detection in accordance with a response time of the communication destination device.