[Coco] 6809 FPGA

[Bill Nobel]

Hey Mark, so if I understand you correctly, do I enable both internal & external RAM at the same time?  Would that not cause memory overlap?

Bill Nobel

> On Oct 7, 2015, at 9:49 PM, Mark McDougall <msmcdoug at iinet.net.au> wrote:
> 
> 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!"
> 
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