[Coco] TCP/IP Programming in Commodore BASIC
sales at gimechip.com
Tue Nov 9 12:58:58 EST 2010
Another solution might be to create a device internal to the CoCo 3. In the
CoCo 3, the $FF1x/$FF3x areas are available for use and a convenient decode
is available at Y3 of the 74LS138 - this pin goes low on the $FF1x/$FF3x
range (note that this is not so for the CoCo 1 and 2 - only the 3). Two
PIA's or other devices could easily be mapped with this select pin. This
select pin could be further decoded so that no mirrors occur and then the
entire range of addresses $FF1x/$FF3x could be used.
----- Original Message -----
From: "Little John" <sales at gimechip.com>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Tuesday, November 09, 2010 11:52 AM
Subject: Re: [Coco] TCP/IP Programming in Commodore BASIC
> $FF8x was used by Paul Barton's memory uprades, but since these aren't
> available anyway, that point is probably moot.
> Earlier Speech Systems (The Voice, SuperVoice, etc.) used the $FF8x range.
> After the advent of the CoCo 3 Speech Systems provided modifications to
> move these to the $FF7x range.
> The primary issue is that once a Multi-Pak has been upgraded to CoCo 3
> compatibility, the $FF8x range is locked out so any $FF8x device will not
> function in an upgraded MPI. It's easy to overcome this with the 26-3024
> by modding the PAL chip to respond to the $FF8x range as I have in my own
> MPI's. The 26-3124 isn't quite so simple to modify to respond to the $FF8x
> range since it has no PAL, but it can be done.
> ----- Original Message -----
> From: <jdaggett at gate.net>
> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> Sent: Tuesday, November 09, 2010 11:46 AM
> Subject: Re: [Coco] TCP/IP Programming in Commodore BASIC
>> On 6 Nov 2010 at 11:27, Gene Heskett wrote:
>>> I am still in favor of the 'chip with a stack' solution, if some way to
>>> squeeze its register addressing into the coco's normal I/O map could be
>>> done. However, I have not investigated today's offerings in that area.
>> 16 Addresses can be fit into the range of $FF80 to $FF8F. As far as I
>> know the GIME chip
>> does not use this block and non of the multitude of the peripherals do
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