[Coco] ROM Cart registers

Mark Marlette mmarlette at frontiernet.net
Mon Feb 1 17:00:53 EST 2016

I am not sure how you can be seeing SCS~ asserted and then applying SLENB~, this will then disable SCS~
and terminate the device's bus cycle before the proper timing has occurred. Pretty sure that is not what you want.
Again, Glenside IDE IO is fully decoded, not SCS and SLENB~ is not used.

I use SLENB~ for advance signaling, not going to get in to why here but is required in my designs.

You CAN NOT have two devices using SLENB~ at the same address, bus conflict will result. Move the sIDE's base address or move yours.
If the end user wanted to have a sIDE and a miniFLASH in the same MPI, one of the devices base address would have to change. All of Boisy's software handles this on the Cloud-9 hardware. It works just fine.
The Gen3 Virtual ROM pack will have an endless amount of packs that it will support, menu driven, configurable with simple ASCII file.

Regards, Mark Marlette
mark at cloud9tech.com

      From: RETRO Innovations <go4retro at go4retro.com>
 To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com> 
 Sent: Monday, February 1, 2016 3:28 PM
 Subject: Re: [Coco] ROM Cart registers
On 2/1/2016 11:44 AM, Mark Marlette wrote:


I do not have a Tandy MPI.  I am trying to acquire one from eBay, but so 
far have been unsuccessful.  Anyone have a spare 3124 MPI (or a 3024 
they want upgraded) they can loan or sell?

Since you say that BASIC should continue to function even after I have 
booted sIDE and switched the slot to another slot, I will check things 
on my end.  I'll try to figure out how the sIDE knows when to put the 
ROM contents onto the bus.  It's possible the ROM contents on this sIDE 
are nonstandard, as I did not install it.

For the record, I am not suggesting there is an issue with the sIDE 
co-existing with any floppy disk controllers.  I am suggesting that the 
sIDE does not co-exist with any other device that decodes at $ff5x on 
the MPI.  I understand your position that such is standard and expected 

I checked the Glenside IDE controller schematic, and (Thanks Tormond and 
Brian) and I cannot find any use of SLENB.  I see it brought out from 
the connector, but not connected to anything.

"You have a conflict, the sIDE has requested that ALL devices be removed 
from the bus via SLENB~. You are not complying to this request, thus you 
are not following the rules for the signal.

It is not a question of why I used the signal in that manner, but why 
you are not complying to the request to remove your device from the bus? "

In this case, my device is ALSO being accessed, so I am driving SLENB to 
remove all other devices off the bus.  SLENB is effectively being 
asserted by 2 devices on the MPI, and neither one is giving up the bus.  
However, I only assert SLENB when I see SCS asserted (implying I am the 
slot that is selected for $ff40-$ff5f activity)


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