[sdiy] Din Sync Master Implementation

[rburnett at richieburnett.co.uk]

On 2014-08-18 15:38, maxrest at gmx.de wrote:
> 
> But would you agree with me that muting the pulses shouldn't do any 
> harm
> to the machine?

It won't harm the machine, but whether it will throw some algorithm 
inside is another thing.  Why don't you try both options:  1. Stopping 
the clock pulses, and 2. De-asserting the run signal but keeping the 
clock pulses going.  The latter is what most DINSYNC outputs tend to do. 
  This gives the receiving device a "preview" of the tempo clock before 
the run signal goes active to start playback.

> I mean they don't implement a PLL or something similar
> that needs to settle and that might mess everything up..

I haven't disassembled the TR-909 ROM code so I really don't know how it 
is done.

For the internal TEMPO clock that is software generated anyway they 
could just run the timer or NCO at 48ppqn speed instead of 24ppqn to get 
the extra shuffle resolution.  But I have no idea how this is done for 
DINSYNC inputs.  I wouldn't be suprised if it acts on the rising and 
falling clock edges.

Maybe you could try setting something up with a couple of debounced 
toggle switches.  One for RUN/STOP and one for TEMPO clock and then try 
manually toggling them very slowly and listening for instruments 
triggering on the rising and falling edges of each clock with different 
shuffle settings.  Then you can see if it only acts on rising clocks, 
acts on rising or falling clocks, or does something else instead like a 
PLL.

-Richie,