[Coco] EEPROM selection

[Patrick Ulland]

Warning, I am an old sysadmin. As such, I identify this as 'the XY 
problem'.

Instead of asking about X (EEPROMs suitable for CoCo motherboard), 
you've already decided a RaspPi will be the solution and now need Y, the 
imaginary 3.3v writable, 5v readable EEPROM to implement the chosen 
solution.

The result, X cannot be solved because there is no solution for Y.

But Y is an added, artificial constraint. Forget assumptions and ask the 
real problem, how do I program a new ECB ROM with minimal external 
hardware. Somebody will have a practical answer to the original question 
that uses cheap chips and maybe a $30 programmer.


-ricku



On 7/28/2024 12:02 PM, dave--- via Coco wrote:
> Since you asked for an EEPROM that could work at *either* 3.3 *or* 5V then the answer is yes. There is not likely an option for an EEPROM that works at both 3.3 *and* 5V though.
>
>
> -Dave Philipsen
>
>> On Jul 26, 2024, at 6:15 PM, coco--- via Coco <coco at maltedmedia.com> wrote:
>>
>> All
>>
>> Is there an EEPROM that can work at either 3.3 or 5 V and can
>> replace the Coco 3 motherboard ROM.
>> I saw an article about how to use the GPIO of a raspberry pi at
>>   https://www.instructables.com/Raspberry-Pi-Python-EEPROM-Programmer/
>> I wondered if such a setup could read a coco ROM and write to a
>> EEPROM chip suitable for a replacing the coco ROM and also
>> which chip would you recommend for this purpose the chip used in
>> the example is 4X the memory of a coco3 ROM.
>>
>> Charlie
>>
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>