[Coco] CocoNIC

RETRO Innovations go4retro at go4retro.com
Sat Sep 24 16:55:17 EDT 2016

On 9/24/2016 3:11 PM, Brett Gordon wrote:
>>       o For everyone's reference, to convert from 65/68XX signalling to
>>         Intel/ISA, here are the equations:
>>           + assign _iow =              !(ce_nic & !r_w & e);
>>           + assign _ior =              !(ce_nic & r_w & e);
>>           + gating with E is important on both read and write
> Thanks for sharing that.  I believe its important to our small community
> that nuggets of helpful info are free and open.  So from the little I
> understand of hardware, it looks as if ISA busses have a separate read and
> write lines, where the m6809 has one?
Yes, Motorola logic (and 65XX, since the MOS guys all came from Moto 
after the 6800), uses CLK (E), !CE, and R/!W, while Intel uses CS (chip 
select), RD, and WR.  Sometimes, CLK is not used, but if not, then CE is 
assumed ot be gated with E if needed.
> All nice features.  Not sure about a coco router, though, I'm guessing the
> code for such would actually be easier than a full tcp/ip stack :)
C'mon, you know you want to try it, if only to say you got it to work.


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