29 Jan
2017
29 Jan
'17
6:55 p.m.
On Sun, 29 Jan 2017 07:41:47 -0800 (PST)
Len Ovens <len(a)ovenwerks.net> wrote:
In NRPN case... things are different. The receiver
should respond to any
one of the four events based on the last received values for the the other
three. It is quite common though in the case of receiving the MSB to check
the following event to see if LSB has changed as well. The four events
should always be sent in order. Events can be left off starting at the
first event, but once one of the events is sent, all following events are
sent.... sort of. The last event is optional (at least some manufactures
treat it so - like Allen & Heath) so a receiver has to check if the last
event is there or not using a short timeout (time to transmit one byte or
event depending on the parser).
Hmm, as a NRPN reciever, I've been doing a variation on that.
I accept Nhigh and Nlow in either order, but only when both are valid respond
to Dhigh and Dlow.
These again I accept in either order and a message is delivered whenever both
are valid (I set 128 as default). After that either can change independently.
This avoids needing timeouts but does mean that sometimes two will be delivered
in rapid sucession. That only happens if changing *both* data bytes without
changing the NRPN.
If either Nhigh or Nlow is changed both Dhigh and Dlow are set to default. I
don't think it's right that changing an NRPN should resend (probably) stale and
incorrect data.
--
Will J Godfrey
http://www.musically.me.uk
Say you have a poem and I have a tune.
Exchange them and we can both have a poem, a tune, and a song.