Content → Hardware → MERG CBUS

• CAN-GC Overview
• CAN-GC1 | CAN-GC1e | CAN-GC2 | CAN-GC3 | CAN-GC4 | CAN-GC5 | CAN-GC6 | CAN-GC7
  • Firmware

The PC interface is not CBUS compatible and works with Rocrail only.

© MERG

This firmware needs a Rocrail CBUS Setup for serial and 230400 bps. (-0,79% tolerance: 228571 bps)
Resonator: 8MHz, Rocrail 2931+.

• https://wiki.rocrail.net/lib/exe/fetch.php?media=cbus:can-gc1.zip

Most RS232 legacy ports cannot handle baud rates above 115200.
To use the needed 230400 baud rate an USB-232 converter is the best solution.
The CAN-GC1 can be equipped with an USB Sub-D type connector.

Compile with the "Case sensitive" option!

• https://gitlab.com/rocrail/GCA/-/tree/master/cbus

The official CBUS protocol is in ASCII which doubles the number of bytes.
To prevent frame loss the response from the CAN-GC1 to Rocrail has been made binary.
An ASCII response starts with ":S" and a binary with ":s".

:ShhhhNd0d1d2d3d4d5d6d7d; :XhhhhhhhhNd0d1d2d3d4d5d6d7d; :ShhhhR; :SB020N;
:S    -> S=Standard X=extended start CAN Frame
hhhh  -> SIDH<bit7,6,5,4=Prio bit3,2,1,0=high 4 part of ID> SIDL<bit7,6,5=low 3 part of ID>
Nd    -> N=normal R=RTR
0d    -> OPC 2 byte HEXA
1d-7d -> data 2 byte HEXA
;     -> end of frame

:shhNd0d1d2d3d4d5d6d7d;
:s    -> s=Standard start CAN Frame
hh    -> SIDH<bit7,6,5,4=Prio bit3,2,1,0=high 4 part of ID> SIDL<bit7,6,5=low 3 part of ID> 2 bytes
Nd    -> N=normal R=RTR 1 byte
0d    -> OPC 1 byte
1d-7d -> data 1 byte
;     -> end of frame (should be a checksum in future versions)

Applications should read up to the OPC to determine the data length.

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