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--- can_communication_with_controllers [2018/05/22 10:33] – external edit 127.0.0.1
+++ can_communication_with_controllers [2019/02/15 14:35] (current) – [SDO CAN frame structure] llibert
@@ Line 21: / Line 21: @@
 > The QuimBox controllers implement a subset of the CANopen protocol. Namely the message layout is completely compatible and the OD concept is reused.
+===== SDO CAN frame structure =====
+An SDO can frame is structured as follow:
+^ Can id  ^  Command byte ^  OD Idx  ^  OD subidx  ^  data  ^
+|  16 bits  |  8 bits  |  16 bits  |  8 bits  |  32 bits  |
+The can id is composed of the RX/TX identifier and the board identifier. (can id = RX/TX-id + Node-id)
+> TX-id = 600
+> RX-id = 580
+Note: RX/TX from host point of view. On board the convention is opposite.
+The command byte is either 0x23 for 32bits writing request, 0x2f for 8bits writing request or 0x40 for reading request (always 32bits response).
+One can test the connection with a linux host using can-utils tools with cansend and candump commands.
+**ex.** A request to enter a QuimDC in operational mode. (32bits write request) (Node-id = 7)
+^ Can id  ^  Command byte ^  OD idx  ^  OD subidx  ^  data  ^^^^
+|  607  |  23  |  3333  |  00  |  01  |  00  |  00  |  00  |
+<code>
+cansend 607#23.3333.00.01.00.00.00
+</code>