T89C51AC2 (CC01 or similar) with EXTRAM (6264)?

Has anyone used T89C51AC2 with external RAM, I'm using it and I have a latch for address, but it isn't working, like some bits are written and some not...

Has anyone done this, are there any problems to be expected.

I use

int xram blablah[4096]

in Keil compiler, and I'm getting signals out of processor, for reading about 200 ns RD, it should be enough for RAM (read and write under 100 ns), but it doesn't work as expected.

I dont have logic anaylzer so it will be tricky to find out what is happening (unfortunately I dont even have storage oscilloscope), so please do write your problems with processor to RAM interface?

Thanx

Reply to
Mickey
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Might be worth looking at your latch circuit. The address I think is valid on the negative transition of ALE, so maybe your latch is latching on the positive edge and causing timing problems? Use a 74HC374 with inverter on clock input or a 74HC373. Also beware of overloading the multiplexed address / data bus if you have other devices hung on it apart from your RAM. These are general 8051 comments and not particularly aimed at your variant.

Reply to
Ppelectron

Use decoupling caps and also select diff mfrs of the 373 or 573 latch. personally never had much luck with the Temic part.

Reply to
Rein Wiehler

on

positive

That was the problem, my colegue connected ALE on /OE and LE to +5V on PCB, and it should have been /OE to GND and LE to ALE.

Thanx on help...

Reply to
MArk

It was the connection problem, thanx on thought anyways.

valid on

positive

input or

if you

8051
Reply to
MArk

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