[Oberon] Digilent Spartan 3 Board

[Chris Burrows]

> -----Original Message-----
> From: Peter De Wachter [mailto:pdewacht at gmail.com]
> Sent: Tuesday, 15 April 2014 4:40 AM
> To: ETH Oberon and related systems
> Cc: chris at cfbsoftware.com
> Subject: Re: [Oberon] Digilent Spartan 3 Board
> 
> On 14-04-14 00:24, Chris Burrows wrote:
> > I would also be interested to know as I am also investigating how I
> > can port it to other hardware. As far as I can see, the only issue
> > with the Digilent
> > Nexys-2 board is that the RAM access speed is 70ns instead of 10ns. Is
> > that a show-stopper? If not what are the consequences of using the
slower
> RAM?
> 
> It's too slow for the current design, isn't it? The CPU runs at 25 MHz =
40ns
> per cycle. But if you halve the frequency to 12.5 MHz, I guess it should
> work.

It would be great if that is the only issue. I suspected there may be
considerations other than that e.g. VGA timing. 

Running at 12.5 MHz is not a problem for me with what I want to do with the
FPGA system. The compiler is super-efficient, modules are dynamically loaded
only when needed, the SDHC access is fast etc. etc. Most of the time I use
RISC Project Oberon the processor is waiting for me to catch up ;-) 

Regards,
Chris

--
Chris Burrows
CFB Software
http://www.cfbsoftware.com