SC1 Extended Accessory Protocol with JMRI & Pi-SPROG

[john174]

Hi - I'm having issues getting the extended accessory protocol modes to work with the SC1.

I'm using JMRI on a Raspberry Pi with the Pi-SPROG command station - with the SC1 in Output address mode (CV29=192)

The normal modes (CV38 between 1 and 19) work fine by sending the appropriate ASON/ASOF CBUS commands (albeit I've found that I have to use an offset of 4 for the address - i.e. CV1=5 and CV9=0 represents a JMRI DCC hardware address of 1 - and ensure I respect 8-address boundaries when configuring it - i.e. allowable base addresses are 1, 9, 17 etc).

However, I can't seem to get  the extended accessory protocol modes to work - all aspects remain dark whatever I send it. 

SC1 Configuration:
-Address mode -  Output address mode (CV29=192)
-Hardware Address - (CV1=5 and CV9=0) - assume this will still represent a hardware address of 1 based on the above
-Decoder Type - 2x 4-aspect using extended accessory protocol (CV38=128)

JMRI Configuration
- Signal Head Type = DCC Signal Decoder
- System = SPROG DCC Generation 5
- Hardware Address = 1
- Offset Address - have tried both modes - checked and unchecked (see below)

Console output (offset unchecked):
JMRI > > CBUS | RDCC4 Repeat: 3 Data: 128 113 0 241 DCC 4 byte pkt (set to red) - Sent: (7f) A0 03 80 71 00 F1
JMRI > > CBUS | RDCC4 Repeat: 3 Data: 128 113 1 240 DCC 4 byte pkt  (set to yellow) - Sent: (7f) A0 03 80 71 01 F0
JMRI > > CBUS | RDCC4 Repeat: 3 Data: 128 113 2 243 DCC 4 byte pkt (set to green) - Sent: (7f) A0 03 80 71 02 F3

Console output (offset checked):
JMRI > > CBUS | RDCC4 Repeat: 3 Data: 129 113 0 240 DCC 4 byte pkt (set to red) - Sent: (7f) A0 03 81 71 00 F0
JMRI > > CBUS | RDCC4 Repeat: 3 Data: 129 113 1 241 DCC 4 byte pkt (set to yellow) - Sent: (7f) A0 03 81 71 01 F1
JMRI > > CBUS | RDCC4 Repeat: 3 Data: 129 113 2 242 DCC 4 byte pkt (set to green) - Sent: (7f) A0 03 81 71 02 F2

Its worth noting that Andrew Crossland confirmed that the Pi-SPROG 3 does have code to support the RDCCx op codes on the SPROG support group

Regards

john

[john174]

May 7, 2021 4:58:58 GMT -5 john174 said:

Hi - I'm having issues getting the extended accessory protocol modes to work with the SC1.

I'm using JMRI on a Raspberry Pi with the Pi-SPROG command station - with the SC1 in Output address mode (CV29=192)

The normal modes (CV38 between 1 and 19) work fine by sending the appropriate ASON/ASOF CBUS commands (albeit I've found that I have to use an offset of 4 for the address - i.e. CV1=5 and CV9=0 represents a JMRI DCC hardware address of 1 - and ensure I respect 8-address boundaries when configuring it - i.e. allowable base addresses are 1, 9, 17 etc).

However, I can't seem to get  the extended accessory protocol modes to work - all aspects remain dark whatever I send it. 

SC1 Configuration:
-Address mode -  Output address mode (CV29=192)
-Hardware Address - (CV1=5 and CV9=0) - assume this will still represent a hardware address of 1 based on the above
-Decoder Type - 2x 4-aspect using extended accessory protocol (CV38=128)

JMRI Configuration
- Signal Head Type = DCC Signal Decoder
- System = SPROG DCC Generation 5
- Hardware Address = 1
- Offset Address - have tried both modes - checked and unchecked (see below)

Console output (offset unchecked):
JMRI > > CBUS | RDCC4 Repeat: 3 Data: 128 113 0 241 DCC 4 byte pkt (set to red) - Sent: (7f) A0 03 80 71 00 F1
JMRI > > CBUS | RDCC4 Repeat: 3 Data: 128 113 1 240 DCC 4 byte pkt  (set to yellow) - Sent: (7f) A0 03 80 71 01 F0
JMRI > > CBUS | RDCC4 Repeat: 3 Data: 128 113 2 243 DCC 4 byte pkt (set to green) - Sent: (7f) A0 03 80 71 02 F3

Console output (offset checked):
JMRI > > CBUS | RDCC4 Repeat: 3 Data: 129 113 0 240 DCC 4 byte pkt (set to red) - Sent: (7f) A0 03 81 71 00 F0
JMRI > > CBUS | RDCC4 Repeat: 3 Data: 129 113 1 241 DCC 4 byte pkt (set to yellow) - Sent: (7f) A0 03 81 71 01 F1
JMRI > > CBUS | RDCC4 Repeat: 3 Data: 129 113 2 242 DCC 4 byte pkt (set to green) - Sent: (7f) A0 03 81 71 02 F2

Its worth noting that Andrew Crossland confirmed that the Pi-SPROG 3 does have code to support the RDCCx op codes on the SPROG support group

Regards

john

[john174]

Hi all

Is anyone able to help/advise on this? - i.e Have I configured everything correctly and is jmri sending the right commands?

Has anyone else out there successfully got the extended accessory protocol to work (either with a SPROG or another command station)?

It won't be the end of the world if I can't get it working but it would make my life easier.

Regards

John

[Paul Harman]

Hi John

I am not sure what all the references to CBUS are doing. You should be sending the commands to the Sprog and not the CBUS interface. Extended accessory commands do work with the Sprog, I use it all the time, I just think that there is something that needs reconfiguring in your JMRI since the Sprog is not a CBUS command station, it has its own serial interface (unless you have a different type of Pi-Sprog).

Paul

[Paul Harman]

Ah, it looks like you might have a 5th-generation Pi-Sprog 3 V2, I have not come across this before, so it will be a bit different to an ordinary Sprog/Pi-Sprog. Andrew has kept this new version quiet.

It will be interesting to see what packets are sent in ordinary mode to compare to the extended mode packets.

[Paul Harman]

Looking at page 32 of the manual would suggest that there might be an address offset of one on CBUS between ordinary accessory addresses and extended accessory addresses, so it might be worth using the jumper address setting feature to set the address of the SC1 to match what is being sent by the Sprog.

[john174]

Hi Paul

Apologies if my original post was confusing. The pi does indeed connect to the pi-sprog via the UART serial interface. This version of the pi-sprog uses the "grid connect" protocol - effectively encoding the MERG cbus-type commands as text strings. Those are the logs I'm reporting in the jmri console output.

All works fine when I configure the sc1 and jmri to use the "normal" control modes - which results in sending ASON and ASOF MERG commands to the pi Sprog.

However, when I configure jmri and the sc1 to use the "extended DCC accessory decoder packet" mode (config details as per the original post) nothing seems to work.

Jmri seems to be generating the correct MERG RDCC4 (Send 4 Byte DCC Packet) command, and Andrew Crossland has confirmed that the pi-sprog supports this - taking the DCC packet encoded in the command and sending it out to the DCC bus. This leads me to conclude there must be an encoding/decoding mismatch - or perhaps I have made a mistake in my configuration?

It would therefore be good to get confirmation that my jmri/sc1 configuration looks "right" and that the jmri encoding scheme matches the sc1 decoding scheme (from what I've read the MERG spec for the "extended DCC accessory decoder packet" is somewhat open to interpretation)

Regards

John

[john174]

Hi Paul - PS - I can't provide an example of the DCC packets sent in "normal" mode without a DCC "sniffer" on the bus. The jmri console only reports the ASON/ASOF commands - with no detail of the DCC packets the pi-sprog turns them into

[john174]

PPS - just seen your last reply. That will teach me to read down to the end of the thread in future. I'll try that as soon as I get another sc1 (the one I've been experimenting with seems to have gone short circuit - but that's probably due to a rogue bit of wire on the workbench 😞)