Casio CZ/ VZ/ FZ - Pro Series

On Sat, Aug 31, 2013 at 07:44:23PM -0000, steve_the_composer wrote:
> Can you be specific--what 7 bytes?
> Did I use those 7 bytes in the tests I previously reported?
> If not, why do you want to send the CZ random 7 bytes?

It's in the protocol.  You start a transfer with:

F0 44 00 00 7x yy pp

where x is the MIDI channel, yy is the command byte and pp is the patch number.

The CZ will respond with:

F0 44 00 00 7x 30

and you respond with:

7x 31

Now, if you send f0 44 00 00 7x yy pp 7x 31 all in one go, USB can handle that because it is (purely by coincidence) a multiple of three bytes - but it crashes the CZ.  Sometimes you get valid patch data, sometimes you get garbage, sometimes you get to do a full reset and clear the RAM.

This doesn't happen if you wait for the request from the CZ.

-- 
Gordonjcp MM0YEQ