JPH06161912A - Data bus control system - Google Patents

Abstract

PURPOSE:To improve the reliability of a data bus in a data bus control system where a data transmitter is connected to plural data receivers via the data buses by preparing a stand-by data bus to replace with any faulty one of those data suses. CONSTITUTION:The working data buses 400-403 are used between a data transmitter 100 and (n) pieces of data receivers 2001-200n. A stand-by data bus 300 is prepared to be replaced with any faulty one of the buses 400-403. The receiver 2001 contains a fault detecting circuit 204 to detect the faults of the transferred data. Meanwhile the transmitter 100 contains a transferred data switching circuit 103 and a selector 104 to switch the faulty one of buses 400-403 to the bus 300. Furthermore the receiver 2001 contains a received data switching circuit 203 and a selector 202 to receive the data via the bus 300.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data bus control system, and more particularly to a data bus fault handling method.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional data bus control system of this type. In the conventional data bus control method, the data sending device 1000 and the first to nth data receiving devices 2000 ₁
To 2000 _n , each of the first to n-th data receiving devices 2000 _{1 to} 2000 _n is connected to the data sending device 1000 via four active data buses 400, 401, 402, and 403. .

The data transmission device 1000 includes a transmission register 101, a bus control circuit 102 for controlling the selection of the data reception device and the timing of the data bus, and transmission data of the transmission register 101 for the active data buses 400 to 40.
3 and four drivers 105 for sending to

First to nth data receiving devices 2000 ₁
Since ~ 2000 _n have the same configuration,
Here, only the first data receiving apparatus 2000 ₁ will be described. The first data receiving device 2000 ₁ includes four receivers 201 for receiving transmission data from the active data buses 400 to 403, a receiving receiver 205 for storing the data received by these receivers 201, and a receiving receiver 205. It has an error check circuit 2001 for checking the presence or absence of a parity error or the like in the received data stored in the receiver 205.

Next, the operation of the conventional data bus control system will be described. When the data transmission device 1000 transmits data, it is assumed that transmission data is prepared in the transmission register 101. Here, the data receiving device to be sent is the first data receiving device 2000 ₁ . In this case, the first data receiving device 2000 ₁ is selected as the data receiving device that the bus control circuit 102 wants to send, and the first enable signal 1 is selected.
Send ₁

The first data receiving device 2000 _{1 that} has received the first enable signal 1 ₁
The transmission data from is received by the reception register 205 via the data buses 400 to 403. Error check circuit 2
001 immediately performs a parity check on the data received by the reception register 205 and confirms whether or not there is an error. If there is no error, it waits for the next data.
Here, when an error is detected, the first data receiving device 2
000 ₁ immediately stops data reception stops transfer operation.

[0007]

As described above, in the conventional data bus control system, when a driver failure or even a partial failure occurs in the data bus, the data bus is common to all data receiving devices. Data cannot be transferred to all data receiving devices connected to the data transmitting device.

Therefore, an object of the present invention is to provide a data bus control system which can ensure the reliability of the data bus.

[0009]

According to the data bus control method of the present invention, a data transmitting device is connected to a plurality of data receiving devices via an active data bus, and data is transferred from the data transmitting device to a plurality of data receiving devices. In the data bus control method for transmitting to any one, a data bus is provided between the data transmitter and the plurality of data receivers to provide a spare data bus that is switched when a failure occurs in the current data bus. Each of the devices has a first means for detecting a failure in the received data and notifying the data sending device of the failure information, and the data sending device has a data path in which a failure has occurred from the failure information received from the first means. To a spare data path and also has a second means for sending a switching instruction signal for switching each of the data receiving devices to the spare data bus. Each is characterized by having a means for receiving data by switching to a spare data bus in accordance with the switching instruction signal from the second means.

[0010]

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

Referring to FIG. 1, a data bus control method according to an embodiment of the present invention includes a data transmitting device 100 and n data receiving devices, that is, _first to _n-th data receiving devices 200 ₁ to 200 _n. It has and. Data transmission device 100 and first to nth data reception devices 200 ₁ to
Each of 200 _n means four active data buses 400 to
Not only is it connected via 403, but it is also connected via a spare data bus 300.

The data transmission device 100 includes a transmission register 1
01, the bus control circuit 102, and the driver 105, as well as the transmission data switching circuit 103 and the selector 104.

The first to nth data receiving devices 200 ₁ to
Since 200 _n have the same configuration, only the first data receiving device 200 ₁ will be described here. The first data receiving device 200 ₁ includes a receiver 20
1 and the reception register 205, four selectors 20
2. Received data switching circuit 203 and fault detection circuit 20
Have four.

The signal lines 1 ₁ to 1 _n are for the _first to _nth enable signals, the signal lines 2 ₁ to 2 _n are for the first to _nth error signals, and the signal lines 3 _{1 to} 3 _n are the first. It is for the first to nth switching instruction signals.

The data transmission apparatus 100 has data required by the _first to _nth data receiving apparatuses 200 ₁ to 200 _n , or the first to nth data receiving apparatuses 200 ₁ to 200 n.
This is a device for transmitting data to be given to 200 _n . The data transmission device 100 provides a parity bit for 8 bits to make 1 byte, and transmits 4 bytes for one data. The transmission register 101 is a register for outputting transmission data. The bus control circuit 102 includes the data transmission circuit 10
First to nth data receiving devices 2 connected under the control of 0
This is a circuit that selects a data receiving device to which data is to be transferred from 00 ₁ to 200 _n and controls the transfer timing of the data bus. The bus control circuit 102 sends the enable signal 1 _i to the selected data receiving device 200 _i (1 ≦ i ≦ n) at the transfer timing of the data bus. The transmission data switching circuit 103 includes the active data buses 400 to 40.
When a failure occurs in any of the three, the data using the failed data bus is used as the spare data bus 3
This is a circuit for switching to 00. Transmission data switching circuit 10
3 is an error signal 2 from a failure detection circuit 204 described later.
_The failure byte is determined from _i , the selector 104 described later switches to the spare data bus 300, and the data receiving device 200 _i switches the data bus by the switching instruction signal 3 _i . The selector 104 is the transmission data switching circuit 1
It is for switching the transmission data by the instruction of 03. The driver 105 has four active data buses 400.
403 to 403 and the spare data bus 300, five are provided to output transmission data to the data bus.

In the first data receiving device 200 ₁ ,
The five receivers 201 are also for receiving the transmission data from the data bus as the reception data. Selector 20
Reference numeral 2 is for switching the reception data according to an instruction from the reception data switching circuit 203 described later, and switches the data of the spare data bus 300 in 1-byte units. The reception data switching circuit 203 is a circuit that causes the selector 202 to switch the reception data according to the first switching instruction signal 3 ₁ .
The failure detection circuit 204 is a circuit that detects a failure in the received data. When a failure is detected by performing a parity check and a failure is detected, the transmission data switching circuit 103 is generated by the first error signal 2 ₁ .
Let us know. The reception register 205 stores the transmission data as the first data.
It is a register that receives and stores at the timing of the enable signal 1 ₁ .

Next, the operation when the data transmission device 100 transmits data will be described. Transmission register 10
When the transmission data can be prepared in 1, the bus control circuit 102 selects the data receiving device to send. Here, assuming that the data receiving device to be sent is the first data receiving device 200 ₁ , the bus control circuit 102 sends the first enable signal 1 ₁ .

The first data receiving apparatus 200 ₁ receiving the first enable signal 1 ₁ receives the transmission data in the reception register 205 via the active data buses 400 to 403. The failure detection circuit 204 immediately performs a parity check on the data received by the reception register 205 and confirms whether or not there is an error. If there is no error, it waits for the next data. Here, it is assumed that an error is detected on the data bus 401 of the second byte of the transmission data. In this case, the failure detection circuit 204 notifies the transmission data switching circuit 103 that the error has been detected at the second byte of the data by the first error signal 2 ₁ .

The transmission data switching circuit 103 which has received the notification
Switches the second byte of the transmission data to the spare data bus 300 by the selector 104, and at the same time, the data transmission device 1
All data receiving devices 200 connected under
_{The first} to _nth switching instruction signals 3 _{1 to} 3 _{n for 1} to 200 _n
Send the second byte of the transmitted data to the spare data bus 3
Notify that you have switched to 00.

The first to nth data receiving devices 200 ₁ to
At 200 _n , the reception data switching circuit 203 follows the instructions of the _first to _nth switching instruction signals 3 _{1 to} 3 _n.
2nd transfer data of 2nd byte is spare data bus 300
To receive via.

[0021]

As described above, according to the present invention, a spare data bus is prepared, and when a failure occurs in the working data bus, the spare data bus is switched to the spare data bus and used to interrupt the operation. Can be prevented. Further, since the data bus is common to all the data receiving devices, even if one failure occurs, data transfer to all connected data receiving devices becomes impossible. However, in the present invention, such a situation occurs. Since it can be avoided, the reliability of the data bus can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a data bus control method when n data receiving devices are connected to a data sending device under a data bus according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a conventional data bus control method in a case where n data receiving devices are connected under a data sending device by a data bus.

[Explanation of symbols]

100 data transmission device 101 transmission register 102 bus control circuit 103 transmission data switching circuit 104 selector 105 driver 200 ₁ to 200 _n data receiving device 201 receiver 202 selector 203 reception data switching circuit 204 fault detection circuit 205 reception register 300 spare data bus 400 To 403 active data bus 1 ₁ to 1 _n enable signal 2 ₁ to 2 _n error signal 3 _{1 to} 3 _n switching instruction signal

Claims (1)

[Claims] 1. A data transmission device is connected to a plurality of data reception devices via an active data bus, and data is transmitted from the data transmission device to any one of the plurality of data reception devices.
In the data bus control method for transmitting data to one of the data transmission devices, a spare data bus is provided between the data transmission device and the plurality of data reception devices, the spare data bus being switched when a failure occurs in the working data bus. Each of the receiving devices has first means for detecting a failure in the received data and notifying the data sending device of the failure information, and the data sending device receives the failure from the failure information received from the first means. Of the data receiving device, the data receiving device is switched to the spare data path, and second switching means for sending a switching instruction signal for switching the data receiving device to the spare data bus is provided. Has means for receiving data by switching to the spare data bus in accordance with the switching instruction signal from the second means. Tabus control method.