== Communication protocol between CAN and CC2540 chip [[BR]] [http://en.wikipedia.org/wiki/CAN_bus] List of commands from CC2540 to CAN transiver: 1. Subscribe to a message 2. Subscribe to a message with a bitmask 3. Unsubscribe from messages 4. Unsubscribe from messages with a bitmask 5. List of all subscriptions 6. Reset filter state 7. Passthrough message {{{ enum { CMD_SUBSCRIBE = 1, CMD_SUBSCRIBE_BITMASK, CMD_UNSUBSCRIBE, CMD_UNSUBSCRIBE_BITMASK, CMD_LIST, CMD_RESET, CMD_MSG } cmd_type; }}} List of responces from CAN transiver: {{{ enum { ACK_SUBSCRIBE = 1, ACK_SUBSCRIBE_BITMASK, ACK_UNSUBSCRIBE, ACK_UNSUBSCRIBE_BITMASK, ACK_LIST, ACK_RESET, ACK_MSG } cmd_type; }}} Command message structure ||= Byte =||= Bitmask =||= Description =||= Values =|| || 0 || || Command code || 1 - 7|| || 1 || || Payload size || 0 - 254|| || 2 - 255 || || Payload |||| Examples {{{ 01:08:00:76:01:55:02:44:00:01 04:02:00:76 05:00 06:00 07:07:FF:05:01:02:03:04:05 }}} 1. byte - subsribe command 2. byte - payload size 8 byte = 2 CAN message IDs * 4 byte each 3. - 10. bytes 0076h & 0155h {{{ ------------------------------------------------- Standard CAN message example: ID=76h byte0 - 07h (incoming CAN MESSAGE) byte1 - 00h (00h=b00000000 bit.7=0 standard message) (this is byte.1 of std.ID excluding high 5 bits in this byte) //if byte1 bit7=0 expect 1 more byte for ID byte2 - 76h (this is byte.0 of std.ID) byte3 - DLC (message data length code. also the payload. 8 in this example) byte4 - 01h (byte.0 of data) byte5 - 02h (byte.1 of data) byte6 - 03h (byte.2 of data) byte7 - 04h (byte.3 of data) byte8 - 05h (byte.4 of data) byte9 - 06h (byte.5 of data) byte10 - 07h (byte.6 of data) byte11 - 08h (byte.7 of data) std.ID example 1 (ID=76h) 07h, 00h,76h, 01h,02h,03h,04h,05h,06h,07h std.ID example 2 (ID=5DFh) 07h, 05h,DFh, 01h,02h,03h,04h,05h,06h,07h ------------------------------------------------- ------------------------------------------------- Extended CAN message example: ID=76h byte0 - 07h (incoming CAN MESSAGE) byte1 - 80h (80h=b10000000 bit.7=1 extended message ) (this is byte.3 of ext.ID excluding high 3 bits in this byte) //if byte1 bit7=1 expect 3 more bytes for ID byte2 - 00h (this is byte.2 of ext.ID) byte3 - 00h (this is byte.1 of ext.ID) byte4 - 76h (this is byte.0 of ext.ID) byte5 - DLC (message data length code. also the payload. 8 in this example) byte6 - 01h (byte.0 of data) byte7 - 02h (byte.1 of data) byte8 - 03h (byte.2 of data) byte9 - 04h (byte.3 of data) byte10 - 05h (byte.4 of data) byte11 - 06h (byte.5 of data) byte12 - 07h (byte.6 of data) byte13 - 08h (byte.7 of data) ext.ID example 1 (ID=76h ( b00000000000000000000000001110110 )) 07h, 80h,00h,00h,76h, 01h,02h,03h,04h,05h,06h,07h ext.ID example 2 (ID=12345678h ( b00010010001101000101011001111000 )) 07h, 92h,34h,56h,78h, 01h,02h,03h,04h,05h,06h,07h ext.ID example 3 (ID=1FFFFFFFh ( b00011111111111111111111111111111 29 bits, max value of ext.ID)) 07h, 9Fh,FFh,FFh,FFh, 01h,02h,03h,04h,05h,06h,07h -------------------------------------------------- }}}