[sdiy] Analysis of the TB-303 CPU timing

Gordonjcp gordonjcp at gjcp.net
Thu Mar 16 19:01:08 CET 2017

On Thu, Mar 16, 2017 at 03:28:27PM -0000, Colin f wrote:
> > While I was working on a reimplementation another guy over at the RE-303
> > forum got this image working running on my AVR based CPU hardware using
> > the MAME code.
> > It runs surprisingly good, but even with a 20MHz clock it has timing
> problems.
> > There is a noticeable lag between clock input and reaction. About 1/2 to
> > 3/4 of a whole clock cycle at medium tempo and the gate off latency seems
> > to be more in the 10ms range than the 2.4ms I measured on the original
> CPU.
> You don't need to run it in real-time to use it to generate precise
> measurements of the jitter & latency you would get from the real machine.
> Did anyone disassemble the hex file to readable text ?

I could maybe take a look if someone has the hex file and a programming guide for the chip?  I'm quite deep into disassembling a car ECU right now but I bet there's hardly anything in the 303.

Gordonjcp MM0YEQ

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