DCC and MRC decodergreenspun.com : LUSENET : Wiring for DCC : One Thread
I'm working on my own DCC trottle, at this time almost everything work, I can setup all CV's ajust speed, lights but I don't know why I have to send each message 2 time to the decoder to make it reconize the message??? Did you have any hints
Thanks for your time Sylvain Bissonnette
-- Sylvain Bissonnette (email@example.com), December 21, 2003
the DCC-Spec explicitely defines, that configuration commands (those, which change CVs) have to be sent twice to the decoder (to be exact: the decoder must sucessfully receive these commands twice). They need not to be sent back to back, but no other command to the decoder being configured is allowed between these two copies of the config command. If the decoder receives any other command in between it has to ignore the previously received config command. Commands to other decoders are explicitely allowed.
But if you have to send normal commands twice then something is wrong. Without further detail I cannot help further.
-- Uli Paul (firstname.lastname@example.org), March 11, 2004.