[Coco] Multi Pack Replacement

[Mark McDougall]

On 25/02/2015 4:07 AM, Camillus Blockx wrote:

> May I ask what FPGA you used, And are there any shematics availlable,
> and verilog/hdl for coco 1/2/3 use?.
> I need schematics to render my new PCB.

There was no one FPGA, it ran on a few FPGA eval/dev boards and a couple of 
proprietary designs for which I do not own the IP. The one thing they had in 
common was that they were all Altera devices.

The back end of WD179x was connected to some FLASH/SRAM which contained a 
_raw_ floppy disk image. It was tested on both NEWDOS/80 and Super Utility 
on the TRS-80 Model III. I never had the hardware to connect it to a 
physical floppy drive, but there's no reason why it shouldn't work with one 
as that was the original intention when I developed it.

The WD179X VHDL source is available as part of my PACEDEV project 
repository. Email me for details.

The IDE controller I used was the OCIDE1 (Opencores) one, which is freely 
available on the net. It was directly connected to a Compact Flash card on 
proprietary hardware, so I am unable to give you the schematics. I'm sure 
there are plenty of reference designs out there you can copy. It ran LDOS 
with Peter Bartlett's Model I ROM extensions.

I also used this core successfully with HDBDOS on my FPGA Coco 1 
implementation on the same hardware platform.

I also have a back-end interface for it that makes an SD card look like an 
IDE drive (written by my colleague). This enabled me to use the 
abovementioned core on the DE1 (same platform as Gary Becker's CocoFPGA) and 
it worked well, albeit in read-only mode as the interface doesn't yet have a 
write mode.

A CF/IDE interface is the easiest to implement but less convenient for the 
user and a much larger pin (I/O) count than SD card. Frankly I'm surprised 
that IDE<->SD card cores aren't available (AFAIK) since it seems to me to be 
a good solution for this type of thing. In any case, either interface is 
well documented and I don't think you'll have problems finding schematics 
for them.

Happy to help out with testing/debug etc if/when you get that far.

Regards,

-- 
|              Mark McDougall                | "Electrical Engineers do it
|  <http://members.iinet.net.au/~msmcdoug>   |   with less resistance!"