[Coco] ROM Cart registers

Darren A mechacoco at gmail.com
Mon Feb 1 16:58:09 EST 2016


On Mon, Feb 1, 2016 at 2:28 PM, RETRO Innovations wrote:

>
> However, I only assert SLENB when I see SCS asserted (implying I am the
> slot that is selected for $ff40-$ff5f activity)
>


That doesn't sound right.  A cartridge asserting SLENB clears the CoCo's
assertion of SCS, which then probably causes you to release SLENB which
then allows the CoCo to re-assert SCS, and so on....

Again, I would recommend never asserting SLENB for any address in the SCS
range. It kills the ability for devices to co-operatively share those
addresses when used together in an MPI. Unfortunately, it has apparently
been established that the sIDE has long done that for $FF5x, so that area
should be considered off-limits for anyone wanting to be compatible with
the device.


- Darren


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