[Coco] 6809 FPGA

[Mark McDougall]

On 8/10/2015 2:44 PM, Bill Nobel wrote:

> Hey all, as some of you know I have been porting Grant Searles
> project to my DE0-Nano.  I have it working with internal ram on the
> Nano itself with 32k ram.  I got my 512k SRAMs from Digikey a week
> ago, (wired as 64k)  when I try to use the SRAM instead of the
> internal RAM  I lose the PS/2 keyboard input.  I get the ‘6809
> EXTENDED BASIC’ banner, and ‘OK’ prompt. but no keyboard.  This is
> running it at 10mhz.  On internal RAM I can do 25mhz no problem.
>
> For the SRAM I have it going to IOBANKS 7 & 8. SRAM address bus &
> chip selects on bank 8 and SRAM data on bank 7.  Video & PS/2 I have
> on bank 5.
>
> Any suggestions would be helpful

Have you tried your design running out of internal RAM but all the SRAM 
pin settings and driving logic in-place? What happens?

Regards,

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