Correct protocol for OPC_IMM_PACKET

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Correct protocol for OPC_IMM_PACKET

Postby big.bear » 25.11.2011, 01:34

Hi, I wonder if anyone can please point me at a reliable description of the packet protocol fort OPC_IMM_PACKET in relation to sending functions F9+

I have a PDF that gives some information and a Rocrail wiki page with more information though it has mistakes when comparing the output with that produced by JMRI ... for example the Address Hi and Lo seem to be the wrong way round.

The main issue I have is with the REPS and DHI bytes. As an example enabling F9 on loco address 1000 yield sin JMRI:

ED 0B 7F 34 07 43 68 21 00 00 5F

If the DHI is suppose to be the top BITS of IM5,4,3,2,1 why is it 7 when IM4 and IM4 are zero (top bits would be zero). This particular aspect of the protocol seems so arbitrary - devised after a particularly good party maybe! (though more likely just evolved as software and protocols do)

Anyway any assistance would be good - I am assuming that JMRI is doing the right thing!

Postby rjversluis » 25.11.2011, 06:50


tnx for the information.
The main problem is that I have no official documentation on how to control functions 8+.
If the example packet is generated by JMRI I will compare it with the one Rocrail generates and trying to fix it.
Best Regards, Rob.
:!: PS: Do not forget to attach the usual files.
:!: PS: Nicht vergessen die übliche Dateien an zu hängen.
[ macOS - Linux] - [ N: CBus - CAN-GCA ] - [ 0: RocNetNode - GCA-Pi ]
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Postby big.bear » 25.11.2011, 15:54

Thanks for the response. If my login works I'll definitely make any necessary corrections, that said I think I am in the same boat without any official protocol. Looks like the only way will be to reverse engineer JRMI unlesss someone here is familiar with that part of the code and can advise.

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