[sdiy] Sync24

[Colin f]

> -----Original Message-----
> From: owner-synth-diy at dropmix.xs4all.nl 
> [mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of 
> Samppa Tolvanen
> Sent: 18 January 2006 14:03
> To: Fredrik Carlqvist
> Cc: synth-diy at dropmix.xs4all.nl
> Subject: Re: [sdiy] Sync24

> On 1/18/06, Fredrik Carlqvist <Fredrik.Carlqvist at iar.se> wrote:
> >
> > What are the signal specs on the Roland Sync24 protocol? I have only
> > found pin numbers so far. I need to know timing, clock 
> pulse lengths,
> > clock polarity etc. Does anyone have a link to something about this?

> The best resource so far: http://www.chd-el.cz/index.php?id=119
> Well, at least for me, pictures tell more than 1000 Chech words..

The pictures are not very accurate though...

The Roland TB303, TR606 and TR808 all poll their sync inputs every ~2ms.
So a clock pulse must be at the very least 2ms long for these devices to see
them.
Roland and Korg equipment I have checked generally don't go any shorter than
4ms pulses, giving an 8ms period which equates to a maximum tempo of 312
bpm.
(Korg used a pulse width of 2ms for the 24 to 48 ppqn conversion on the
KMS30, which implies that must be the minimum width for 48ppqn.
Each 24ppqn pulse triggers a 2ms pulse, 2ms space, 2ms pulse, giving the
required clock doubling.)

The CLOCK line must also be reset before the RUN line goes high, and CLOCK
must remain low for at least 8ms after the positive edge on RUN. Otherwise,
and 808 CPU (and possibly also 303 and 606, though I don't think this is
specifically documented) may not have time to initialise itself.

Cheers,
Colin f