[Coco] Extended Basic Upgrade Options

Dave Philipsen dave at davebiz.com
Tue Apr 7 14:07:42 EDT 2015


Just another thought....in my opinion if you are going to replace the 
ROM in your CoCo it is a better idea to go ahead and modify it to use at 
2764 EPROM.  In general, I believe the 2764 is more reliable.

On 4/7/2015 12:31 PM, Al Hartman wrote:
> One would guess Tandy did this because that kind of masked ROM was 
> cheaper, and it made it less likely the average user would pirate a 
> ROM rather than taking their Coco to a Computer Center to purchase a 
> real one.
>
>
> -[ Al ]-
>
>
> On Tue, Apr 07, 2015 at 01:21 PM, Dave Philipsen wrote:
>
>> Yes, but that's only a 32k-bit EPROM which means it's 4K-byte and not 
>> large enough for the BASIC ROM in a CoCo.
>>
>> The problem is that whoever designed the CoCo decided to use the 
>> 68764 pinout for the ROMs which is different from the defacto 
>> industry standard 2764.  Apparently Commodore used this ROM in the 
>> C64 as well.
>>
>> Dave Philipsen
>
>



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