[BBC-Micro] Reversing the Tube ULA (destructively)
jules.richardson99 at gmail.com
Tue Oct 26 14:01:01 BST 2010
John Kortink wrote:
> On Mon, 25 Oct 2010 20:34:48 -0500, Jules Richardson
> <jules.richardson99 at gmail.com> wrote:
>> Also, is it *that* hard to reverse-engineer and produce a pin-compatible
>> equivalent? (maybe a smaller IC of some form on a carrier board?) Why the need
>> to try and clone the actual chip from visual inspection - simply for
>> curiosity? (A noble enough reason ;)
> Um ... Hello ?
> ReTuLa (which I announced some time ago on this very
> mailing list ...) is an exact copy of the Tube ULA.
> Albeit with two caveats : a smaller VDU FIFO, and no
> DMA. These could both be fixed quite easily, but would
> require a different (faster, bigger) logic chip.
Yeah, sorry! I should have mentioned that I was aware of yours. I just had it
in the back of my head that your one wasn't *quite* 100% (just very close!)
and that you'd chosen not to release details of the internals because it was
done as something of a commercial venture (my assumption being that Ed was
aiming for a 100% compatible, documented, open replacement - but maybe I'm
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