Re: GAL vs CPLD

From: Michał Pleban <*lists_at_michau.name*> Date: Tue, 18 Sep 2012 10:18:40 +0200 Message-ID: <50582E60.9040600@michau.name> · lists_at_michau.name

Hello!

didier derny wrote:

> I know that they are bot pin compatible
> my question should have been:
> can I do with a CPLD all I can do with a GAL ?

Yes, and much more.

> actually on the main cpld, I have
> - 12 bits of address A15-A4  (for the register and the exclusion in
> $FFF0-$FFFF
> -   8 bits of data  for the register and experiment
> -   4 bits for the selection of the page in ram
> -   1 bit  den signal
> -   1 bit cs for sram
> -   1 bit cs for eprom
> -   1 bit used but I dont remember for what :(

OK, that is 28 lines which is exactly how many you can extract from your
CPLD now :-) I would suggest narrowing your data bus to 4 bits, and
using more than one register instead. Internally you will still have the
same number of latches, but outwardly it will require less pins. This
will save you pins and you will have some free for your experiments.

Regards,
Michau.

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