[Coco] EEPROM replacement for 27C256

[John B]

Thanks.  I was looking at the data sheet for the 29C256 and it seems to be
pin for pin compatible with the 27C256.  Pin 1 is VSS on the 27C256 and W/E
on the 29C256.  I ordered a few off eBay and when my TL886 gets here I will
program one to see if it works.

On Sun, Jun 28, 2015 at 12:17 AM, Dave Philipsen <dave at davebiz.com> wrote:

> There is a 28C256 that is as probably as close as you'll get in terms of
> pinout.  It won't be an exact drop-in replacement, though, as the A14 pin
> changes position and you'll have to come up with a write enable as,
> obviously, the 27C256 which is a primarily read-only device does not have.
> I have a 28C256 floating around here somewhere that I used in a custom
> circuit I built one time but I've never tried to wire it up to a CoCo3.
> One thing for sure, you'd have to make sure that any changes written to the
> EEPROM contain no undesirable code that could cause the CoCo to become
> unbootable.  Otherwise you'd have to pull the 28C256 and re-program it out
> of circuit.
>
> Dave Philipsen
>
> On 6/25/2015 2:43 PM, John B wrote:
>
>> Does anyone know of a suitable EEPROM replacement for the 27C256 found in
>> the CoCo3?
>>
>>
>
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