JPH0535513A - Bus adaptor - Google Patents

Abstract

PURPOSE:To attain the transfer of data by controlling the addition or the non- addition of a CRC code to the data to be transferred, thereby connecting both a device containing a CRC function and a device containing no CRC function to a single bus. CONSTITUTION:A device connected to a bus consists of a dip switch which works according to the presence or absence of 8 CRC function, the selectors 3 end 4 which perform the switch between the data with a CRC code and the data with no CRC code, and a device ID recognizing part 1 which outputs the switch instructions of the selectors 3 and 4. When the data are transferred to a device 100 containing the CRC function, a CRC control part 2 adds a CRC code to the data and sends this data to the selector 3. Meanwhile the data are sent to the selector 3 with no addition of the CRC code when the data are transferred to device 10-1 containing no CRC function. Then the selector 3 selects the data given through a host bus 1 and sends the data to a follower bus 501 with the instruction of the part 1. Then the selector 4 is used in place of the selector 3 when the data transfer direction is reversed between both buses 1 and 501.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bus adapter,
In particular, it relates to a bus adapter for exchanging data via a bus.

[0002]

2. Description of the Related Art Conventionally, there is no device capable of mixing and connecting a device having a CRC function and a device having no CRC function on one bus. Generally, only a device having a CRC function or no CRC function is provided. It was necessary to build a network with only the devices.

[0003]

The above-mentioned conventional technique has a drawback in that it is not possible to connect a device having a CRC function and a device having no CRC function together on one bus.

[0004]

According to the bus adapter of the present invention, in a bus adapter for transferring data to a bus, a CRC code is added to the transfer data when the data is transferred to a device having a cyclic redundancy check function. A means for transferring data without adding a CRC code to the transfer data when transferring the data to a device that does not have the function, and checking the CRC code when receiving the data from the device having the CRC function, and checking the CRC function. Means for not performing CRC check when receiving data from a device that does not have it.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

In FIG. 1, 10-0 to 10-N are devices connected to a lower bus, and are mainly CRTs.
It is connected to a display unit, printer, plotter, keyboard, flexible disk, hard disk, etc.

The CRC control unit 2 adds a CRC code to the data at the time of transferring the data to the device with the CRC function, and when the data is input from the device with the CRC function, the CRC control unit 2
The data is checked by using the C code, and the data excluding the CRC code part from the data part is sent to the selector 4 through the signal line 202. The selector 3 switches between transferring data with a CRC code or transferring data without a CRC code at the time of data transfer to the device. The data excluding the CRC code is selected, and the data from the lower bus is selected when the data is input from the device without the CRC function.

The dip switch 5 is a device 10-0.
10-N is set according to whether each has a CRC function. The device ID recognition unit 1 operates the devices 10-0 to 10-10 by the DIP switch 5.
It judges whether -N has a CRC function or not, and issues a switching instruction to the selector 3 when data is transferred to the device, and issues a switching instruction to the selector 4 when data is input from the device.

Next, the operation of transferring data to the CRC function device 10-0 will be briefly described. First, the device ID recognition unit 1 recognizes that the device 10-0 is a device with a CRC function by using the DIP switch 5. The CRC control unit 2 adds a CRC code to the data from the upper bus 100 and sends it to the selector 3 via the signal line 201. Selector 3 is device ID recognition unit 1
The data with the CRC code from the signal line 201 is selected according to the above instruction and sent to the lower bus 501.

Subsequently, the device 10-1 without the CRC function
A brief description will be given of the operation when data is transferred to.
That is, the device ID recognition unit 4 uses the DIP switch 5
Recognizes that the device 1 is a device without a CRC function. Then, the selector 3 selects data from the upper bus 100 according to an instruction from the device ID recognition unit 1 and sends it to the lower bus 501.

Further, when the data transfer direction between the upper bus 100 and the lower bus 501 is reversed, the selector 3
, The signal line 202 is used instead of the signal line 201, and the signal line 401 is used instead of the signal line 301.
Becomes clear by substituting each with a passing signal.

[0012]

As described above, according to the present invention, by controlling whether or not the CRC code is added to the transfer data, the device having the CRC function and the device not having the CRC function on one bus. There is an effect that and can be mixed and connected.

[Brief description of drawings]

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

[Explanation of symbols]

 1 Device ID recognition unit 2 CRC control unit 3, 4 selector 5 DIP switch 10-0 to 10-N device

Claims (1)

Claim: What is claimed is: 1. In a bus adapter for transferring data to a bus, CRC is transferred to the transfer data when the data is transferred to a device having a cyclic redundancy check (hereinafter referred to as "CRC") function.
A means for transferring data without adding the CRC code to the transfer data when adding the code and transferring the data to the apparatus having no CRC function, and checking the CRC code when receiving the data from the apparatus having the CRC function Do C
CR when receiving data from a device that does not have RC function
A data transfer device comprising means for not checking C.