[BBC-Micro] Reversing the Tube ULA (destructively)

John Kortink kortink at inter.nl.net
Tue Oct 26 10:13:08 BST 2010


On Mon, 25 Oct 2010 20:34:48 -0500, Jules Richardson
<jules.richardson99 at gmail.com> wrote:

>Ed Spittles wrote:
>> Even more ideally, someone already has some high-resolution photos of
>> the chip, or the original artwork...
>
>Hmm, anyone know who had a hand in the design? I could maybe poke a few 
>contacts and ask "do you know how to reach such-and-such?", if I knew who I 
>need to be asking after :-)
>
>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.

I say 'exact' because I tested its state transitions
extensively, and I'm pretty confident that even in
pathetic cases it does the exact same thing as the
original.


John Kortink

-- 

Email    : kortink at inter.nl.net
Homepage : http://www.inter.nl.net/users/J.Kortink

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