obd2.cpp

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/*
 * @file obd2.cpp
 *
 * ISO 15765-4
 * http://en.wikipedia.org/wiki/OBD-II_PIDs
 *
 * @date Jun 9, 2015
 * @author Andrey Belomutskiy, (c) 2012-2020
 *
 * This file is part of rusEfi - see http://rusefi.com
 *
 * rusEfi is free software; you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * rusEfi is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program.
 * If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "pch.h"
 
#if EFI_CAN_SUPPORT
 
#include "obd2.h"
#include "can.h"
#include "can_msg_tx.h"
#include "fuel_math.h"
 
static const int16_t supportedPids0120[] = { 
    PID_MONITOR_STATUS,
    PID_FUEL_SYSTEM_STATUS,
    PID_ENGINE_LOAD,
    PID_COOLANT_TEMP,
    PID_STFT_BANK1,
    PID_STFT_BANK2,
    PID_INTAKE_MAP,
    PID_RPM,
    PID_SPEED,
    PID_TIMING_ADVANCE,
    PID_INTAKE_TEMP,
    PID_THROTTLE,
    -1
};
 
static const int16_t supportedPids2140[] = {
    PID_FUEL_AIR_RATIO_1,
    -1
};
 
static const int16_t supportedPids4160[] = { 
    PID_FUEL_RATE,
    -1
};
 
static void obdSendPacket(int mode, int PID, int numBytes, uint32_t iValue, size_t busIndex) {
    CanTxMessage resp(CanCategory::OBD, OBD_TEST_RESPONSE);
 
    // Respond on the same bus we got the request from
    resp.busIndex = busIndex;
 
    // write number of bytes
    resp[0] = (uint8_t)(2 + numBytes);
    // write 2 bytes of header
    resp[1] = (uint8_t)(0x40 + mode);
    resp[2] = (uint8_t)PID;
    // write N data bytes
    for (int i = 8 * (numBytes - 1), j = 3; i >= 0; i -= 8, j++) {
        resp[j] = (uint8_t)((iValue >> i) & 0xff);
    }
}
 
#define _1_MODE 1
 
static void obdSendValue(int mode, int PID, int numBytes, float value, size_t busIndex) {
    efiAssertVoid(ObdCode::CUSTOM_ERR_6662, numBytes <= 2, "invalid numBytes");
    int iValue = (int)efiRound(value, 1.0f);
    // clamp to uint8_t (0..255) or uint16_t (0..65535)
    iValue = maxI(minI(iValue, (numBytes == 1) ? 255 : 65535), 0);
    obdSendPacket(mode, PID, numBytes, iValue, busIndex);
}
 
 
//#define MOCK_SUPPORTED_PIDS 0xffffffff
 
static void obdWriteSupportedPids(int PID, int bitOffset, const int16_t *supportedPids, size_t busIndex) {
    uint32_t value = 0;
    // gather all 32 bit fields
    for (int i = 0; i < 32 && supportedPids[i] > 0; i++)
        value |= 1 << (31 + bitOffset - supportedPids[i]);
 
#ifdef MOCK_SUPPORTED_PIDS
    // for OBD debug
    value = MOCK_SUPPORTED_PIDS;
#endif
 
    obdSendPacket(1, PID, 4, value, busIndex);
}
 
static void handleGetDataRequest(const CANRxFrame& rx, size_t busIndex) {
    int pid = rx.data8[2];
    switch (pid) {
    case PID_SUPPORTED_PIDS_REQUEST_01_20:
        obdWriteSupportedPids(pid, 1, supportedPids0120, busIndex);
        break;
    case PID_SUPPORTED_PIDS_REQUEST_21_40:
        obdWriteSupportedPids(pid, 21, supportedPids2140, busIndex);
        break;
    case PID_SUPPORTED_PIDS_REQUEST_41_60:
        obdWriteSupportedPids(pid, 41, supportedPids4160, busIndex);
        break;
    case PID_MONITOR_STATUS:
        obdSendPacket(1, pid, 4, 0, busIndex);  // todo: add statuses
        break;
    case PID_FUEL_SYSTEM_STATUS:
        // todo: add statuses
        obdSendValue(_1_MODE, pid, 2, (2<<8)|(0), busIndex);    // 2 = "Closed loop, using oxygen sensor feedback to determine fuel mix"
        break;
    case PID_ENGINE_LOAD:
        obdSendValue(_1_MODE, pid, 1, getFuelingLoad() * ODB_TPS_BYTE_PERCENT, busIndex);
        break;
    case PID_COOLANT_TEMP:
        obdSendValue(_1_MODE, pid, 1, Sensor::getOrZero(SensorType::Clt) + ODB_TEMP_EXTRA, busIndex);
        break;
    case PID_STFT_BANK1:
        obdSendValue(_1_MODE, pid, 1, 128 * engine->stftCorrection[0], busIndex);
        break;
    case PID_STFT_BANK2:
        obdSendValue(_1_MODE, pid, 1, 128 * engine->stftCorrection[1], busIndex);
        break;
    case PID_INTAKE_MAP:
        obdSendValue(_1_MODE, pid, 1, Sensor::getOrZero(SensorType::Map), busIndex);
        break;
    case PID_RPM:
        obdSendValue(_1_MODE, pid, 2, Sensor::getOrZero(SensorType::Rpm) * ODB_RPM_MULT, busIndex); //  rotation/min.   (A*256+B)/4
        break;
    case PID_SPEED:
        obdSendValue(_1_MODE, pid, 1, Sensor::getOrZero(SensorType::VehicleSpeed), busIndex);
        break;
    case PID_TIMING_ADVANCE: {
        float timing = engine->engineState.timingAdvance[0];
        timing = (timing > 360.0f) ? (timing - 720.0f) : timing;
        obdSendValue(_1_MODE, pid, 1, (timing + 64.0f) * 2.0f, busIndex);       // angle before TDC.    (A/2)-64
        break;
        }
    case PID_INTAKE_TEMP:
        obdSendValue(_1_MODE, pid, 1, Sensor::getOrZero(SensorType::Iat) + ODB_TEMP_EXTRA, busIndex);
        break;
    case PID_INTAKE_MAF:
        obdSendValue(_1_MODE, pid, 2, Sensor::getOrZero(SensorType::Maf) * 100.0f, busIndex);   // grams/sec    (A*256+B)/100
        break;
    case PID_THROTTLE:
        obdSendValue(_1_MODE, pid, 1, Sensor::getOrZero(SensorType::Tps1) * ODB_TPS_BYTE_PERCENT, busIndex);    // (A*100/255)
        break;
    case PID_FUEL_AIR_RATIO_1: {
        float lambda = clampF(0, Sensor::getOrZero(SensorType::Lambda1), 1.99f);
 
        uint16_t scaled = lambda * 32768;
 
        obdSendPacket(1, pid, 4, scaled << 16, busIndex);
        break;
    } case PID_FUEL_RATE: {
        float gPerSecond = engine->module<TripOdometer>()->getConsumptionGramPerSecond();
        float gPerHour = gPerSecond * 3600;
        float literPerHour = gPerHour * 0.00139f;
        obdSendValue(_1_MODE, pid, 2, literPerHour * 20.0f, busIndex);  //  L/h.    (A*256+B)/20
        break;
    } default:
        // ignore unhandled PIDs
        break;
    }
}
 
static void handleDtcRequest(int numCodes, ObdCode* dtcCode) {
    // TODO: this appears to be unfinished?
    UNUSED(numCodes);
    UNUSED(dtcCode);
 
    // int numBytes = numCodes * 2;
    // // write CAN-TP Single Frame header?
    // txmsg.data8[0] = (uint8_t)((0 << 4) | numBytes);
    // for (int i = 0, j = 1; i < numCodes; i++) {
    //  txmsg.data8[j++] = (uint8_t)((dtcCode[i] >> 8) & 0xff);
    //  txmsg.data8[j++] = (uint8_t)(dtcCode[i] & 0xff);
    // }
}
 
#if HAL_USE_CAN
void obdOnCanPacketRx(const CANRxFrame& rx, size_t busIndex) {
    if (CAN_SID(rx) != OBD_TEST_REQUEST) {
        return;
    }
 
    if (rx.data8[0] == _OBD_2 && rx.data8[1] == OBD_CURRENT_DATA) {
        handleGetDataRequest(rx, busIndex);
    } else if (rx.data8[0] == 1 && rx.data8[1] == OBD_STORED_DIAGNOSTIC_TROUBLE_CODES) {
        // todo: implement stored/pending difference?
        handleDtcRequest(1, &engine->engineState.warnings.lastErrorCode);
    } else if (rx.data8[0] == 1 && rx.data8[1] == OBD_PENDING_DIAGNOSTIC_TROUBLE_CODES) {
        // todo: implement stored/pending difference?
        handleDtcRequest(1, &engine->engineState.warnings.lastErrorCode);
    }
}
#endif /* HAL_USE_CAN */
 
#endif /* EFI_CAN_SUPPORT */