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
- Committer:
- foxdie
- Date:
- 2013-04-08
- Revision:
- 8:bc97fa5d306e
- Parent:
- 7:5ec65e6e8095
- Child:
- 9:4af02032daeb
File content as of revision 8:bc97fa5d306e:
/* GMLAN.cpp - Source file for GMLAN Library GMLAN is a Controller Area Network Bus used in General Motors vehicles from roughly 2007-onwards. Its purpose is to allow various Electronic Control Units (aka ECUs) within a modern vehicle to share information and enact procedures. An example of this would be communication between the HU (Head unit) and the DIC (Dashboard Information Cluster), when you adjust the volume up / down, this is reported to the cluster to be displayed. It is the function of this library to "crack open" this world to allow anyone with only as little as a few hours of C++ programming under their belt to get started in what can sometimes seem a daunting world. Jason Gaunt, 18th Feb 2013 */ #include "mbed.h" #include "GMLAN.h" #include <vector> void CANHeader::decode(int _header) { if (_header < 0x800) { // 11-bit header arbitrationID = (_header >> 0) & 0x7FF; } else { // 29-bit header priorityID = (_header >> 26) & 0x7; arbitrationID = (_header >> 13) & 0x1FFF; senderID = (_header >> 0) & 0x1FFF; } } int CANHeader::encode29bit(void) { long int buffer = 0; buffer = (buffer << 3) | 0x0; // 3 bit padding buffer = (buffer << 3) | priorityID; buffer = (buffer << 13) | arbitrationID; buffer = (buffer << 13) | senderID; return buffer; } int CANHeader::encode11bit(void) { short int buffer = 0; buffer = (buffer << 5) | 0x0; // 5 bit padding buffer = (buffer << 11) | arbitrationID; return buffer; } GMLAN_Message::GMLAN_Message(int _priority, int _arbitration, int _sender, int _b0, int _b1, int _b2, int _b3, int _b4, int _b5, int _b6, int _b7) { priority = _priority; arbitration = _arbitration; sender = _sender; if (_b0 != -1) data.push_back(_b0); if (_b1 != -1) data.push_back(_b1); if (_b2 != -1) data.push_back(_b2); if (_b3 != -1) data.push_back(_b3); if (_b4 != -1) data.push_back(_b4); if (_b5 != -1) data.push_back(_b5); if (_b6 != -1) data.push_back(_b6); if (_b7 != -1) data.push_back(_b7); } CANMessage GMLAN_Message::generate(void) { CANHeader hdr; hdr.priority(priority); hdr.arbitration(arbitration); hdr.sender(sender); char datatochars [data.size()]; for (int i = 0; i < data.size(); i++) datatochars[i] = data[i]; if (sender > 0x0) return CANMessage(hdr.encode29bit(), datatochars, data.size(), CANData, CANExtended); else return CANMessage(arbitration, datatochars, data.size(), CANData, CANStandard); } GMLAN_11Bit_Request::GMLAN_11Bit_Request(int _id, vector<char> _request, bool _await_response, bool _handle_flowcontrol) { id = _id; request_data = _request; await_response = _await_response; handle_flowcontrol = _handle_flowcontrol; tx_bytes = rx_bytes = 0; tx_frame_counter = rx_frame_counter = 1; const char _fp [8] = {0xAA,0xAA,0xAA,0xAA,0xAA,0xAA,0xAA,0xAA}; memcpy(frame_padding, _fp, 8); request_state = GMLAN_STATE_READY_TO_SEND; } CANMessage GMLAN_11Bit_Request::getNextFrame(void) { char datatochars [8]; memcpy(datatochars, frame_padding, 8); if (handle_flowcontrol == true) { // Only run this section if we need flow control if (request_data.size() < 8) { // Unsegmented frame datatochars[0] = (GMLAN_PCI_UNSEGMENTED << 4) | (request_data.size() & 0xF); for (int i = 0; i < request_data.size(); i++) { datatochars[i+1] = request_data[i]; tx_bytes++; } request_state = GMLAN_STATE_AWAITING_REPLY; } else if (tx_bytes == 0) { // First segmented frame datatochars[0] = (GMLAN_PCI_SEGMENTED << 4) | ((request_data.size() >> 8) & 0xF); datatochars[1] = request_data.size() & 0xFF; for (int i = 0; i < 6; i++) { datatochars[i+2] = request_data[i]; tx_bytes++; } request_state = GMLAN_STATE_AWAITING_FC; } else if (tx_bytes <= request_data.size()) { // Additional segmented frame with data left to transmit datatochars[0] = (GMLAN_PCI_ADDITIONAL << 4) | (tx_frame_counter & 0xF); int old_tx_bytes = tx_bytes; for (int i = old_tx_bytes; i < old_tx_bytes + 7; i++) { if (i >= request_data.size()) break; datatochars[(i+1)-old_tx_bytes] = request_data[i]; tx_bytes++; } tx_frame_counter++; if (tx_frame_counter > 0xF) tx_frame_counter = 0x0; } if (tx_bytes >= request_data.size()) { if (await_response == true) request_state = GMLAN_STATE_AWAITING_REPLY; else request_state = GMLAN_STATE_COMPLETED; } } else { // No flow control required, build the frames without parsing but make sure we don't overshoot 8 bytes for (int i = 0; i < request_data.size(); i++) { if (i < 8) { datatochars[i] = request_data[i]; tx_bytes++; } else break; } if (await_response == true) request_state = GMLAN_STATE_AWAITING_REPLY; else request_state = GMLAN_STATE_COMPLETED; } return CANMessage(id, datatochars, 8, CANData, CANStandard); } CANMessage GMLAN_11Bit_Request::getFlowControl(void) { request_state = GMLAN_STATE_AWAITING_REPLY; GMLAN_Message buffer = GMLAN_Message(0x0, id, 0x0, 0x30, 0x0, 0x0); return buffer.generate(); } void GMLAN_11Bit_Request::processFrame(CANMessage msg) { if (((msg.id & 0xFF) == (id & 0xFF)) && (request_state == GMLAN_STATE_AWAITING_REPLY)) { // Only handle requests we've instigated char datatochars [8]; memcpy(datatochars, msg.data, 8); if (((datatochars[0] >> 4) & 0xF) == GMLAN_PCI_UNSEGMENTED) { // Unsegmented frame rx_bytes = (datatochars[0] & 0xF); if (datatochars[1] == GMLAN_SID_ERROR) { // Error frame if ((rx_bytes == 3) && (datatochars[3] == 0x78)) return; // "Still processing request" message, ignore this one request_state = GMLAN_STATE_ERROR; } else request_state = GMLAN_STATE_COMPLETED; for (int i = 1; i < (rx_bytes+1); i++) response_data.push_back(datatochars[i]); } else if (((datatochars[0] >> 4) & 0xF) == GMLAN_PCI_SEGMENTED) { // First segmented frame rx_bytes = (datatochars[0] & 0xF); rx_bytes = (rx_bytes << 8) | datatochars[1]; for (int i = 2; i < 8; i++) { if ((i - 2) >= rx_bytes) { // Safety net for incorrectly formatted packets request_state = GMLAN_STATE_COMPLETED; return; } response_data.push_back(datatochars[i]); } request_state = GMLAN_STATE_SEND_FC; } else if (((datatochars[0] >> 4) & 0xF) == GMLAN_PCI_ADDITIONAL) { // Additional segmented frame // TODO check for frame order for (int i = 1; i < 8; i++) { if (response_data.size() >= rx_bytes) { request_state = GMLAN_STATE_COMPLETED; return; } response_data.push_back(datatochars[i]); } if (response_data.size() >= rx_bytes) { request_state = GMLAN_STATE_COMPLETED; return; } } else if (((datatochars[0] >> 4) & 0xF) == GMLAN_PCI_FLOW_CONTROL) { // Flow control frame request_state = GMLAN_STATE_SEND_DATA; } } }