JPH0481141A - Command transfer method - Google Patents

Abstract

PURPOSE:To reduce a rate of a transfer command being an important command considerably by adopting a command in common to an error check code for the important command to a slave system and not using commands different by prescribed bits from the important command. CONSTITUTION:A system stop command is a data having a 6-bit value of '010101' and 1's complement for high-order 3 bits is used for a level for low- order 3 bits. A command 'b' is a command different by one bit from the system stop command 1 and commands transferred in error as the system stop com mand different by one bit from the system stop command 1 are commands 'b'. Then the commands 'b' are not used as usual commands but remaining commands shown in space in table are used for usual commands. Thus, any command transferred in one bit error is not the system stop command and a rate causing a detrimental mistake due to erroneous command transfer is remarkably reduced.

Description

[Detailed Description of the Invention] [Summary] Regarding a method of transferring commands from a master system to a slave system in communication between multiple independent systems, the purpose is to enable error detection of important commands. In the command transfer method from the main system to the slave system, among the commands transferred from the main system, important commands for the slave system are commands that also serve as error detection codes, and commands that have a value different from the important command by a predetermined bit are used. is an unused command, all commands other than the important command and the unused command are normal commands, and when the unused command is input to the slave system, the command transferred from the main system is handled as an error. Configure it like this.

[Industrial application field]

The present invention relates to a command transfer method, and more particularly to a method of transferring commands from a master system to a slave system in communication between a plurality of independent systems.

As an example of communication between a plurality of independent systems, for example, as shown in FIG. 3, there is a system in which commands are transferred from a main system 1 to a slave system 2 to control the display on a display device 3. In such a system, it is necessary that the slave system 2 be able to perform error detection for particularly important commands among the operation commands of the slave system 2.

[Conventional technology]

Conventionally, in a display system as shown in FIG. 3, when controlling the display of the display device 3 by commands transferred from the main system 1 to the slave system 2, if an error detection code is added to all commands and transferred, the amount of communication is reduced. However, even if there is a transfer error in the command due to noise or the like, most of the errors will be displayed on the display device 3, and considering that the error rate is not high in a closed system, the error detection code is Therefore, the slave system 2 does not have error detection means. Thereby, the display device 3 can be easily controlled by the main system 1.

[Invention or problem to be solved]

However, among the commands that are transferred, there are not only commands related to display characters, but also commands that are transferred very infrequently, commands that stop the operation of the slave system 2, and commands that set the slave system 2 in a test mode.

If a command related to a display character or a command related to another display character is mistakenly transferred to the slave system 2, the impact on the system user will be small because the display character is incorrect, or the transferred command may be affected by noise, etc. If the command to stop the operation of the slave system 2 is mistakenly transferred to the slave system 2, the slave system 2 will stop even though it was not intended because conventional methods do not detect errors. Until the data is input to the slave system 2, the display will not appear, causing a serious operational failure. If the test mode command is mistakenly forwarded, it will similarly cause a serious system failure.

The present invention has been made in view of the above points, and an object of the present invention is to provide a command transfer method that enables error detection of important commands.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a method for transferring commands from a main system to a slave system, in which a command important to the slave system among transferable commands is set as a command that also serves as an error detection code. Commands with different values in only the specified bits are treated as unused commands.
Other commands are treated as normal commands, and when an unused command is input to the slave system, the command transferred from the main system is handled as an error.

[Effect]

If the important command is mistakenly input to the slave system as the important command, a serious problem unintended by the master system or a serious problem will occur in the slave system. However, in the present invention, since the important command is transferred also as an error detection code, the rate of a transfer command becoming an important command due to a transfer error can be significantly reduced.

〔Example〕

FIG. 1 shows a command explanatory diagram of an embodiment of the present invention. In the figure, A indicates the top 3 bits, B indicates the bottom 3 bits, and "
"B" indicates the system stop command as the important command. In other words, the system stop command is rolo
This data has a 6-bit value lolJ. In this embodiment, a 3-bit two-wire code is used for the system stop command, and the value is either the 1's complement of the upper 3 bits or the lower 3 bits.

Further, in FIG. 1, "mouth" indicates a command having a one-bit value different from the above-mentioned system stop command.

That is, most of the commands that are erroneously transferred as the system stop commands indicated by "A" are commands that have a 1-bit value different from the system stop commands indicated by the above "g". Therefore, in this embodiment, the commands indicated by "mouth" are not used as normal commands, and the values in the remaining blank spaces in FIG. 1 are assigned to normal commands. As a result, according to this embodiment, the system stop command will not be sent incorrectly due to a single pit error, and the rate of serious problems caused by incorrect command transfer can be greatly reduced. Even if 1 bit is wrong, it can be easily detected.

FIG. 2 shows a configuration diagram of an embodiment of the present invention. In the figure, the same components as those in FIG. 3 are designated by the same reference numerals, and their explanations will be omitted. In FIG. 2, the slave system 2 includes a serial-to-parallel converter circuit 21. Command latch circuit 22, command decoder 2
3. and a display device control section 24.

The main system 1 transfers each command assigned in the method shown in FIG.
Transfer serially to 1. A 6-bit command serially-parallel-converted and taken out in parallel by the serial-parallel conversion circuit 21 is temporarily stored in the command latch circuit 22, and then inputted to the command decoder 23 and decoded. This command decoder 23 decodes the parallel input commands, and when the decoding result of the system stop command shown as "A" in FIG. When the decoding result of the command shown in Figure 1 is obtained, an error detection signal is sent to the main system 1 via the terminal, and the value in the blank part of Figure 1 is sent. When the decoding result of each command related to display characters and color information is obtained, a signal corresponding to the value of the command is sent to the display device control unit 24 via terminal C for normal operation control other than system stoppage.

In this way, when a system stop command is transferred and received normally, a system stop control signal is sent to the display device control unit 24, and when a 1-bit error occurs even though the system stop command has been transferred, An error notification is sent to the main system 1.

Furthermore, since a command with a value that would result in a system stop command due to a 1-bit error is not originally used, it is possible to prevent the system from stopping due to a 1-bit error.

Note that the present invention is not limited to the above-described embodiment, and for example, settings similar to those shown in FIG. 1 may be made for other important commands, and important commands may be It is also possible to disable the use of commands that have two pit values or different values.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to significantly reduce the proportion of transfer commands or transfer errors that result in serious commands that seriously impede the operation of the slave system. It has features such as being able to significantly improve the reliability of communication between

[Brief explanation of the drawing]

FIG. 1 is a command explanatory diagram of an embodiment of the present invention, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is a block diagram of an example of a system to which the present invention can be applied. In the figure, 1 is a main system, 2 is a slave system, 3 is a display device, and 23 is a command decoder.

Claims (1)

[Claims] In a method for transferring commands from a main system (1) to a slave system (2), among commands transferred from the main system, important commands for the slave system (2) are encoded with an error detection code. A command that has a value different from the important command by a predetermined bit is an unused command, a command other than the important command and the unused command is a normal command, and the unused command is used as a slave system command. A command transfer method characterized in that when the command is input to the main system, error processing is performed on the command transferred from the main system.