NWE pulse problem

[nugoori72]

I want use external memory IC(IDT 7204 FIFO memory)

I use two STM32H743II(one is write FIFO, one is read FIFO)

I think read was good work.

but write is not good.

I set FMC LCD Interface like Cubeset picture

I think one data write operation, NWE pulse appear 1 time.

but when one data write, 4 NWE pulse shown.(refer tek0009 scope data)

write code is like below.

*(__IO uint16_t *) FIFO_D = rCnt;

4 NWE pulse is normal status?

[waclawek.jan]

All signals for static memories and similar parallel interfaces are qualified by the NEx (chipselect) signal, so you should observe also that signal.

JW

[nugoori72]

NE1 is two pulse.

why 2 pulse?

[waclawek.jan]

Well, I don't know.

Does the address/data remain the same, i.e. does it write the same data to the same address twice? If yes, it can't be considered an error - static memories wouldn't care about it, it's just ineffective. It even may be documented - look into the errata.

JW