Jason Gaunt / GMLAN

Libraries to support working with GMLAN - General Motors CAN BUS network in most of their vehicles between 2007-present day. Please note this is a work in progress and not guaranteed to be correct, use at your own risk! Read commit logs / subscribe to see what has been added, it's a work in progress after all ;)

GMLAN.cpp@0:9266fbfbef88, 2013-02-19 (annotated)

Committer:
foxdie
Date:
Tue Feb 19 17:12:53 2013 +0000
Revision:
0:9266fbfbef88
Child:
3:09fdfec053cd
Initial version commit supporting decoding of 29 bit GMLAN headers only at this point. More to come :)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
foxdie 0:9266fbfbef88 1 /*
foxdie 0:9266fbfbef88 2 GMLAN.cpp - Source file for GMLAN Library
foxdie 0:9266fbfbef88 3
foxdie 0:9266fbfbef88 4 GMLAN is a Controller Area Network Bus used in General Motors vehicles from
foxdie 0:9266fbfbef88 5 roughly 2007-onwards. Its purpose is to allow various Electronic Control Units
foxdie 0:9266fbfbef88 6 (aka ECUs) within a modern vehicle to share information and enact procedures.
foxdie 0:9266fbfbef88 7
foxdie 0:9266fbfbef88 8 An example of this would be communication between the HU (Head unit) and the
foxdie 0:9266fbfbef88 9 DIC (Dashboard Information Cluster), when you adjust the volume up / down, this
foxdie 0:9266fbfbef88 10 is reported to the cluster to be displayed.
foxdie 0:9266fbfbef88 11
foxdie 0:9266fbfbef88 12 It is the function of this library to "crack open" this world to allow anyone
foxdie 0:9266fbfbef88 13 with only as little as a few hours of C++ programming under their belt to get
foxdie 0:9266fbfbef88 14 started in what can sometimes seem a daunting world.
foxdie 0:9266fbfbef88 15
foxdie 0:9266fbfbef88 16 Jason Gaunt, 18th Feb 2013
foxdie 0:9266fbfbef88 17 */
foxdie 0:9266fbfbef88 18
foxdie 0:9266fbfbef88 19 #include "GMLAN.h"
foxdie 0:9266fbfbef88 20
foxdie 0:9266fbfbef88 21 void CANHeader::decode(int _header) {
foxdie 0:9266fbfbef88 22 priorityID = (_header >> 26) & 0x7;
foxdie 0:9266fbfbef88 23 arbitrationID = (_header >> 13) & 0x1FFF;
foxdie 0:9266fbfbef88 24 senderID = (_header >> 0) & 0x1FFF;
foxdie 0:9266fbfbef88 25 }
foxdie 0:9266fbfbef88 26 int CANHeader::encode(void) {
foxdie 0:9266fbfbef88 27 long int buffer = 0;
foxdie 0:9266fbfbef88 28 buffer = (buffer << 3) | 0x0; // 3 bit padding
foxdie 0:9266fbfbef88 29 buffer = (buffer << 3) | priorityID;
foxdie 0:9266fbfbef88 30 buffer = (buffer << 13) | arbitrationID;
foxdie 0:9266fbfbef88 31 buffer = (buffer << 13) | senderID;
foxdie 0:9266fbfbef88 32 return buffer;
foxdie 0:9266fbfbef88 33 }