[BBC-Micro] Reversing the Tube ULA (destructively)
jules.richardson99 at gmail.com
Tue Oct 26 13:32:29 BST 2010
Rick Murray wrote:
> On 26/10/2010 05:53, Phill Harvey-Smith wrote:
>> I believe his clone, doesn't have as many bytes in it's FIFOs,
> Yes, I remember, though this could just be a limitation of the
> programmable logic he used - that adding a larger FIFO would not have
> provided suitable gains for the work involved?
>> and I seem to remember him saying that it didn't do DMA I think,
> The Tube does DMA!?
> I suppose the question is, do we want an EXACT replica, or "something
> that works"?
Personally, I want a drop-in "open" replacement which behaves (electrically
and from a software point of view) exactly like the original. "mechanically"
is less of an issue, I think - yes, it'd be great if it were just a 40-pin
DIP, but I think most (if not all) of the copros had a reasonable amount of
clearance around the socket such that a slightly larger footprint would still
Exactly *how* the replacement is arrived at, I don't care - e.g. whether it's
from analysing the original hardware, finding the original designs, studying
the documentation, studying software that uses the TUBE etc.
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