JPH01271994A - Method for writing data to eprom - Google Patents

Abstract

PURPOSE:To make a decoder to select a page mode terminal unnecessary and to reduce a cost by previously writing 1 to all the bits in the latch circuit of an EPROM in a page mode. CONSTITUTION:For the writing modes of respective EPROMs 10a-10d, the writing mode of an EPROM out of the above-mentioned EPROMs, for which data writing is selected, and the level a terminal CS is made into a low level, is a byte writing mode, and the writing modes of the other EPROMs are a page writing mode. As the result, for the EPROMs for which data writing is not selected, the contents of latch circuits 11 are written to memory cells 12 in the page writing mode. Thereupon, actually no data are written to the memory cells 12 even when the data are written from the latch circuits 11 to the memory cells 12 in the page writing mode by previously writing '1' to all the bits in the latch circuits 11 of the EPROMs. Consequently, the decoder to control a terminal PGM becomes unnecessary, and the cost of the hardware can be reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an EPROM writing method, and particularly to an EPROM writing method.
This invention relates to an EFROM writing method in which an OM is mounted on a printed board and written into it.

[Conventional technology]

EPROM has a small chip size relative to the amount of data that can be written, and can be rewritten a predetermined number of times, so it is widely used in numerical control devices, robot control devices, and the like.

On the other hand, these control devices require a considerable number of EFROMs, and usually a considerable number of EFROMs are mounted on one printed board. Then, data is written into each EFROM in the mounted state.

Furthermore, in an EFROM having a storage capacity of approximately IM bits, there are a byte write mode and a page write mode as methods for writing data. When using an EPROM alone, the page write mode has a faster (and better) write speed.

[Problem to be solved by the invention]

However, the E
Decoder to select PROM and EPRO to write
Two decoders are required, one for selecting the page mode terminal of M. Such a decoder is necessary only when writing to the EPROM, and is unnecessary when the printed board on which the EPROM is mounted is mounted in a control device and used.

The present invention has been made in view of these points, and is
This is an EPROM writing method in which the PROM is mounted on a printed board and written to it, and is an EF method that reduces the number of decoders.
The purpose is to provide a ROM writing method.

[Means to solve the problem]

In the present invention, in order to solve the above problems, in an EPROM writing method in which the EPROM is mounted on a printed board and written, data 1 is written to all bits of the launch circuit of the EPROM in page mode, and data 1 is written to all bits of the launch circuit of the EPROM in the byte mode. An EFROM writing method is provided, which is characterized by selecting and writing data.

[Effect]

If data I is written in the latch circuit of the EFROM in the page mode before data is written in the byte mode, there is no need to control the page control terminal, and a decoder for selecting the page control terminal becomes unnecessary.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

Figure 3 shows an overview of EPROM. In the figure, 10 is an EPROM, 11 is a latch circuit, and there is a latch inside. 12 is a memory cell. A bus 13 includes both an address bus and a data bus. Terminal C3 is a terminal for chip selection, and terminal PGM is a terminal for selecting page mode.

EPROM10 has two types of write modes.

The first mode is a byte write mode, in which the terminal C3 and the terminal PGM are set to low level. At this time, data is directly written into the memory cell without passing through the latch circuit 11.

The second mode is a page write mode, in which the terminal C3 is set to low level and the terminal PGM is set to high level.

At this time, since the write data is once electrically written into the latch circuit 11, the writing speed from the outside becomes high.

FIG. 1 is a block diagram of a printed circuit board mounted with an EFROM for implementing the present invention. In the figure, 1 is a memory board, 2 is an address bus, and 3 is a data bus. 4 is a decoder, which receives a chip selection terminal signal C51.
=C3n is output.

10a to 10d are EPROMs, in which four E
Although it represents a PROM, in reality, a large number of EFROMs are installed as necessary.

The decoder 3 selects the C8 terminal of each EPROM to be written into, but the terminal PGM is at a low level. Therefore, each EPROM10a to 10
In the write mode of d, write is selected and the terminal C8
The EPROM in which the is at a low level is in the byte write mode, and the other EPROMs are in the page write mode. As a result, E
The PROM is in page write mode, and the contents of the latch circuit 11 shown in FIG. 3 are written into the memory cell 12.

. In order to solve this problem, in the present invention, "i'1" is written in all bits of the launch circuit 11 of the EPROM in advance. Since all bits in the EPROM before writing are F14, even if data is written from the launch circuit 11 to the memory cell 12 in the page write mode, nothing is actually written. As a result, a decoder for controlling the terminal PGM is not required, and the hardware cost is reduced.

FIG. 2 shows a flowchart for implementing the present invention. In the figure, the number following S indicates the step number.

[S1] Set the address to O.

[S2] In page mode, set all bits of the latch circuit to “
1”.

[S3] Select the required EPROM in byte mode and write data. In the unselected EPROM, the C3 terminal is at a high level, and the data i'lJ of the latch circuit is written to page-T--, but nothing is actually written.

[S4] Check whether the written data is normal, and if it is normal, proceed to S5.
If it is not normal, go to S6.

[S5] Check the final address, and if it is not the final address, add 1 to the address and proceed to S2.

[S6] Since the written data is defective and there is a defective EFROM on the printed board, writing is stopped and an alarm is displayed.

Although this embodiment has been described for one type of page write mode, other page write modes can be implemented using the same concept.

〔Effect of the invention〕

As explained above, in the present invention, in advance in page mode,
Since 1 is written in all bits of the PROM latch circuit, a decoder for selecting the page mode terminal is not required, and the cost is reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a printed circuit board equipped with an EFROM for implementing the present invention, FIG. 2 is a flowchart for implementing the present invention, and FIG. 3 is a diagram showing an outline of the EPROM. 1------------Memory board 2---
−−−−−−−−−Address bus 3−−−−−−−
−・−−−1・Data bus 10・−1−−−−−−・−
-----E P ROMl 0 a ~ 10 d...
・・−=−−−E P ROMll−・−・・−・−・
・Latch circuit 12−・−・・−・・−・・−・Memory cell 2nd circle diagram 3

Claims (1)

[Claims] (1) EPROM is mounted on a printed board and written to it.
A ROM writing method characterized by writing data 1 to all bits of a latch circuit of an EPROM in a page mode, and selecting an EPROM to be written to and writing data in a byte mode.