JPH02292650A - System for detecting rom errorneous mounted - Google Patents

Abstract

PURPOSE:To easily detect the insertion of errorneous ROM such as ROM in which a different program exists by setting the output of a decoder part to be true only when ROM where the conventional program of a device is written is mounted. CONSTITUTION:When ROM 3 which the device concerned requires is mounted on the space of ROM 3, the program is arranged in such a way that the out instruction of '80' is continuously outputted twice, for example. When the power of the device is supplied, a PWCL signal is impressed on an output holding part 5 through a signal line 7, and the diode of a display part 6 is lighted. When ROM 3 in which the accurate program is written is inserted, data of '80' is transmitted to a data bus. Since there is a case that the same out-instruction is accidentaly outputted in different ROM at that time, the instruction is continuously outputted twice, and errorneous decision is prevented. When data of '80' is transmitted twice, the signal is transmitted to the output holding part 5 by the action of a decoder part 4, and the diode of the display part 6 is switched off.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device equipped with a CPU, and more particularly to a circuit for determining the contents of a ROM in which a program is stored.

(Prior Art) Conventionally, a device in which a CPU executes processing based on a program in a ROM has not been equipped with a means for detecting incorrect mounting of the ROM.

(Problem to be solved by the invention) Conventionally, ROM in which data other than the program to be used in the device is written, and RO in which the contents are erased
There is a drawback that if a ROM with M or nothing written is inserted, or if a ROM is inserted with the right and left sides reversed, the error cannot be detected immediately.

An object of the present invention is to have a decoder section that operates based on program operation Vζ in a device equipped with a microprocessor, and the output of the decoder section is limited only when a ROM in which the original program of the device is written is mounted. To provide a ROM erroneous mounting detection method configured to eliminate the above drawbacks by informing the outside that the output of the decoder section is true, and to easily detect errors in ROM contents. There is a particular thing.

<Means for Solving Problem ea) The ROM erroneous mounting detection method according to the present invention is configured to include a ROM, a decoder section, and a display section.

The ROM is a ROM in which data identifying itself is written together with a program.

The decoder section decodes the contents of the ROM and obtains a true output only when the original program is written.

The display section is for notifying the external K of the true output.

(Implementation row) Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram illustrating one implementation of the R OM mismounting detection method according to the present invention.

In FIG. 1, 1 is a CPU, 2 is an address decoder,
5 is a ROM, 4 is a decoder section, 5 is an output holding section, 6 is a display section, 7 is a PWCL signal line, and 8 is a flip-flop, respectively.

In FIG. 1, the ROMall mounting detection method according to the present invention includes a microprocessor 1, a ROM 3 in which a program for controlling the microprocessor 1 is written, a decoder section 4, an output holding section 5, and an output holding section 5. It consists of a display part B that lights up with the output of.

In FIG. 1, when the ROM δ required by the device is installed in the ROM 5 space, the program is set up so that, for example, an out command of %80I is output twice in succession. Although the data %80' is listed here, it is also possible to set different data by replacing the AND gate of the decoder section 4 shown in FIG.

Next, the operation of the present invention will be explained with reference to FIG.

When the device is powered on, a PWCL signal is applied to the output holding section 6 via the signal line 7, and the diode of the display section 6 lights up. When a ROM δ in which a correct program is written is inserted, data called data path VC%801 is sent out. At that time, the same out command may be issued by chance in different ROMs, so this command is
The data is output repeatedly to prevent erroneous judgments.

(Effects of the Invention) As explained above, the present invention has a decoder section which operates according to the operation of a program in a device K equipped with a microprocessor, and an RO in which the original program of the device is written.
When M is implemented, the output of the decoder section is true for K only, and by letting the outside know that the output of the decoder section is true, it is necessary for the panel to be inserted upside down, for example. If a certain ROM was not installed correctly, if a ROM with a different program was inserted, if a new ROM was inserted with nothing written in it, or if the ROM's contents have been erased.
If M is inserted, the K alarm lamp lights up, so that an error in the ROM contents can be immediately discovered.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating one implementation of the ROM stack detection method according to the present invention. 1●●●CPU 2●●−Address decoder 3●●●ROM ●Decoder section●Output holding section/display section/signal line●Φ●Flip-flop patent applicant

Claims (1)

[Claims] A ROM in which self-identifying data is written together with a program, a decoder section that decodes the contents of the ROM and obtains a true output only when the original program is written, and a decoder section that decodes the contents of the ROM and obtains a true output only when the original program is written. 1. A ROM mounting error detection method, comprising: a display section for notifying the outside.