[Coco] MC6847 External Character ROM

[Zippster]

I rethought how I might do this.  I guess I’d only need 3 address locations.

Back to studying the service manual memory map… :)

- Ed


> On Jan 22, 2015, at 9:50 PM, Zippster <zippster278 at gmail.com> wrote:
> 
> Anyone have any suggestions for memory locations to decode for IO
> to sich a setup?  Is there any room amongst the IO devices on the main board?
> I don’t want to interfere with anything.
> 
> I’d like to stay away from SCS* and CTS* if I can to avoid conflicting with peripheral cards.
> 
> I’m looking for 7 bytes if I can get it.
> 
> - Ed
> 
>> On Jan 16, 2015, at 8:15 PM, Luis Antoniosi (CoCoDemus) <retrocanada76 at gmail.com> wrote:
>> 
>> I a nice improvement would be using SRAM and allowing the coco to change it
>> on the fly using some port. The SRAM would be dumped from ROM upon reset.
>> 
>> Just in case you end up without any other project ;)
>> 
>> 
>> 
>> Luis Felipe Antoniosi
>> 
>> 
>> 
>> On Fri, Jan 16, 2015 at 9:02 PM, Zippster <zippster278 at gmail.com> wrote:
>> 
>>> The earlier style (USA) CoCo2’s are socketed that I’ve seen.
>>> A lot of the later (Korean) ones would need a socket installed.
>>> 
>>> - Ed
>>> 
>>> 
>>>> On Jan 16, 2015, at 7:49 PM, Allen Huffman <alsplace at pobox.com> wrote:
>>>> 
>>>>> On Jan 16, 2015, at 7:42 PM, Zippster <zippster278 at gmail.com> wrote:
>>>>> 
>>>>> I’ve got my External Character ROM prototype for the MC6847 working.
>>>>> There’s a few pics I put up here if anyone is interested in taking a
>>> look.
>>>> 
>>>> 
>>>> Wow. That takes me back. I need to crack open my CoCo 1 and see what
>>> model lowercase mod I had in it. It wasn’t the big brand — something
>>> cheaper… That’s really neat. I think my VDG was socketed on the CoCo 1.
>>>> 
>>>> I assume later CoCo’s had it soldered to the motherboard? Soldering
>>> would be required to install?
>>>> 
>>>> --
>>>> Allen Huffman - PO Box 22031 - Clive IA 50325 - 515-999-0227 (vmail/TXT
>>> only)
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>>>> Sent from my MacBook.
>>>> 
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>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
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