[Coco] MC6847 External Character ROM

[Luis Antoniosi (CoCoDemus)]

You can use the FF78, FF79. Use the first as command port and the second as
data port. This port is the same I used for my wordpak2+.

Luis Felipe Antoniosi



On Fri, Jan 23, 2015 at 8:48 AM, Zippster <zippster278 at gmail.com> wrote:

> I’d have to design a board that provides access to the IO select signals on
> the 74LS138 and both the address and data bus to allow for this,
> so all the signals would be there.  The logic would just have to be worked
> out.
>
> I’m trying to stay away from the cart port signals for the internal mods
> though.
>
> - Ed
>
>
> > On Jan 23, 2015, at 12:00 AM, RETRO Innovations <go4retro at go4retro.com>
> wrote:
> >
> > On 1/22/2015 11:32 PM, Zippster wrote:
> >> Well, I think I’ve found an abundance of unused locations if I’ve read
> the SAM
> >> datasheets, CoCo2 memory map and schematic correctly.  96 unused
> addresses
> >> listed as ‘reserved for future use or special io’ (FF60-FFBF).
> >> They don’t seem to be used by either the 74LS783 or 74LS785 SAM
> versions,
> >> so if they do actually light up y7 as they should on the 74LS138 (IC11)
> I can
> >> use them for all kinds of stuff.
> >
> > Would it be possible to set one byte as an MMU to remap the char rom
> (ram) into another slot in the Coco?
> >
> >
> >
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > https://pairlist5.pair.net/mailman/listinfo/coco
>
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> https://pairlist5.pair.net/mailman/listinfo/coco
>