>Are the some limits on how many times you can prgaming a 16c84??
>I have some problems wit some chips(I can use them,but not enabel to
>progaming them)
>Arne - norway

Arne,

EEPROM devices have a maximum number of write cycles specified. The Data
EEPROM is rated a 1,000,000 write cycles. The 16C84 program memory I cannot
find specified but it should be at the very least 1000 cycles and more
likely to be 10,000.

Thats a lot of program cycles!

If you cannot program them at all then its not likely to be that the EEPROM
cells have died. I would expect in that case to get a small number of
failures first and not across a number of devices all of a sudden.

Either the chips could be damaged or you programmer is not 100%  Are the
devices that fail a different batch from those that work? The code is on the
bottom line and looks like 9534CBN or 9525 CBA.

Devices from different batch numbers have small differences in programming
time and current consumption etc.

It's hard to guess what is wrong as you haven't provided much detail. Please
let me know the following and maybe I can help more:

Are the failing chips code protected and the working chips not?

Did the chips program before with the same programmer?

What sort of programmer are you using?

The batch number of the failing chips.

I do not believe it's likely you have reached the end of the useful life of
the chips but I don't know for certain.

Regards,

Jim

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