[Coco] Glenside IDE + Multi-Pak + HDB-DOS

[Barry Nelson]

I would not clone the existing Glenside device, it can be improved on. First, if you want to allow it to work with a Floppy controller without a MPI, add pass through connector for the floppy to plug into, and have your device disable the SCS line on that connector when any address from FF50-FF7F is accessed. The floppy only needs to use FF40-FF4F for it to work. It should also disable the CTS line on that pass through connector if your card's on board ROM is active. That will prevent any I/O conflict with the floppy. Secondly, when your card is using an I/O port from FF40-FF5F it should disable it's I/O if SCS is not active. Also, it should not respond to any access to FF7F SCS or not. If the card only requires FF70-FF78, then it should fully decode those addresses. Any ROM on the card should only be active when the CTS is low, and I you might want to have a way of disabling the ROM completely. A simple jumper disconnecting the CTS line would do this. If you disable the on board ROM you could enable the CTS line on the pass through connector, but this may not be needed if you have a programable ROM. What ever you would use need to use in an external slot as far as ROM is concerned could be copied to the on board ROM instead and the external ROM could be be left disabled.

> Mark J. Blair nf6x at nf6x.net 
> Sun Sep 11 21:30:21 EDT 2016
> > On Sep 11, 2016, at 17:56, Robert Gault <robert.gault at att.net> wrote:
> > 
> > Someone who owns the Glenside IDE and an MPI needs to determine which unit or software fails with the IDE set to $FF7x. You should not assume that the hardware forces use of $FF5x because it might be possible to alter the READ routines in HDBDOS to compensate for the "timing error" mentioned by Boisy.
> 
> I have both a Glenside IDE and an MPI sitting on a full test bench, so maybe I can help figure out what the issue is. I'll email Boisy to see if he's interested in dusting off the brain cells to look at this again.