From 8e57c683d3d16f1dee320f10c411602ea38ba651 Mon Sep 17 00:00:00 2001 From: Stanley Huang Date: Mon, 25 Mar 2013 00:57:28 +0800 Subject: initial commit --- libraries/OBD/OBD.cpp | 269 ++++++++++++++++++++++++++++++++++++++++++++++++++ libraries/OBD/OBD.h | 84 ++++++++++++++++ 2 files changed, 353 insertions(+) create mode 100644 libraries/OBD/OBD.cpp create mode 100644 libraries/OBD/OBD.h (limited to 'libraries') diff --git a/libraries/OBD/OBD.cpp b/libraries/OBD/OBD.cpp new file mode 100644 index 0000000..b3da34e --- /dev/null +++ b/libraries/OBD/OBD.cpp @@ -0,0 +1,269 @@ +/************************************************************************* +* OBD-II (ELM327) data accessing library for Arduino +* Distributed under GPL v2.0 +* Copyright (c) 2012 Stanley Huang +* All rights reserved. +*************************************************************************/ + +#include +#include +#include "OBD.h" + +#define INIT_CMD_COUNT 7 +#define MAX_CMD_LEN 6 + +const char PROGMEM s_initcmd[INIT_CMD_COUNT][MAX_CMD_LEN] = {"ATZ\r","ATE0\r","ATL1\r","ATI\r","0100\r","0120\r","0140\r"}; +const char PROGMEM s_searching[] = "SEARCHING"; +const char PROGMEM s_cmd_fmt[] = "%02X%02X 1\r"; +const char PROGMEM s_cmd_sleep[MAX_CMD_LEN] = "atlp\r"; +const char PROGMEM s_response_begin[] = "41 "; + +unsigned int hex2uint16(const char *p) +{ + char c = *p; + unsigned int i = 0; + for (char n = 0; c && n < 4; c = *(++p)) { + if (c >= 'A' && c <= 'F') { + c -= 7; + } else if (c>='a' && c<='f') { + c -= 39; + } else if (c == ' ') { + continue; + } else if (c < '0' || c > '9') { + break; + } + i = (i << 4) | (c & 0xF); + n++; + } + return i; +} + +unsigned char hex2uint8(const char *p) +{ + unsigned char c1 = *p; + unsigned char c2 = *(p + 1); + if (c1 >= 'A' && c1 <= 'F') + c1 -= 7; + else if (c1 >='a' && c1 <= 'f') + c1 -= 39; + else if (c1 < '0' || c1 > '9') + return 0; + + if (c2 >= 'A' && c2 <= 'F') + c2 -= 7; + else if (c2 >= 'a' && c2 <= 'f') + c2 -= 39; + else if (c2 < '0' || c2 > '9') + return 0; + + return c1 << 4 | (c2 & 0xf); +} + +void COBD::Query(unsigned char pid) +{ + char cmd[8]; + sprintf_P(cmd, s_cmd_fmt, dataMode, pid); + WriteData(cmd); +} + +bool COBD::ReadSensor(byte pid, int& result, bool passive) +{ + if (passive) { + bool hasData; + unsigned long tick = millis(); + while (!(hasData = DataAvailable()) && millis() - tick < OBD_TIMEOUT_SHORT); + if (!hasData) { + errors++; + return false; + } + } else { + Query(pid); + } + return GetResponse(pid, result); +} + +bool COBD::DataAvailable() +{ + return OBDUART.available(); +} + +char COBD::ReadData() +{ + return OBDUART.read(); +} + +void COBD::WriteData(const char* s) +{ + OBDUART.write(s); +} + +void COBD::WriteData(const char c) +{ + OBDUART.write(c); +} + +char* COBD::GetResponse(byte pid, char* buffer) +{ + unsigned long startTime = millis(); + byte i = 0; + + for (;;) { + if (DataAvailable()) { + char c = ReadData(); + buffer[i] = c; + if (++i == OBD_RECV_BUF_SIZE - 1) { + // buffer overflow + break; + } + if (c == '>' && i > 6) { + // prompt char reached + break; + } + } else { + buffer[i] = 0; + unsigned int timeout; + if (dataMode != 1 || strstr_P(buffer, s_searching)) { + timeout = OBD_TIMEOUT_LONG; + } else { + timeout = OBD_TIMEOUT_SHORT; + } + if (millis() - startTime > timeout) { + // timeout + errors++; + break; + } + } + } + buffer[i] = 0; + + char *p = buffer; + while ((p = strstr_P(p, s_response_begin))) { + p += 3; + if (pid == 0 || hex2uint8(p) == pid) { + errors = 0; + p += 2; + if (*p == ' ') + return p + 1; + } + } + return 0; +} + +bool COBD::GetParsedData(byte pid, char* data, int& result) +{ + switch (pid) { + case PID_RPM: + result = GetLargeValue(data) >> 2; + break; + case PID_FUEL_PRESSURE: + result = GetSmallValue(data) * 3; + break; + case PID_COOLANT_TEMP: + case PID_INTAKE_TEMP: + case PID_AMBIENT_TEMP: + result = GetTemperatureValue(data); + break; + case PID_ABS_ENGINE_LOAD: + result = GetLargeValue(data) * 100 / 255; + break; + case PID_MAF_FLOW: + result = GetLargeValue(data) / 100; + break; + case PID_THROTTLE: + case PID_ENGINE_LOAD: + case PID_FUEL_LEVEL: + result = GetPercentageValue(data); + break; + case PID_SPEED: + case PID_BAROMETRIC: + case PID_INTAKE_PRESSURE: + result = GetSmallValue(data); + break; + case PID_TIMING_ADVANCE: + result = (GetSmallValue(data) - 128) >> 1; + break; + case PID_DISTANCE: + case PID_RUNTIME: + result = GetLargeValue(data); + break; + default: + return false; + } + return true; +} + +bool COBD::GetResponse(byte pid, int& result) +{ + char buffer[OBD_RECV_BUF_SIZE]; + char* data = GetResponse(pid, buffer); + if (!data) { + // try recover next time + WriteData('\r'); + return false; + } + return GetParsedData(pid, data, result); +} + +bool COBD::GetResponsePassive(byte& pid, int& result) +{ + char buffer[OBD_RECV_BUF_SIZE]; + char* data = GetResponse(0, buffer); + if (!data) { + // try recover next time + return false; + } + pid = hex2uint8(data - 3); + return GetParsedData(pid, data, result); +} + +void COBD::Sleep(int seconds) +{ + char cmd[MAX_CMD_LEN]; + strcpy_P(cmd, s_cmd_sleep); + WriteData(cmd); + if (seconds) { + delay((unsigned long)seconds << 10); + WriteData('\r'); + } +} + +bool COBD::Init(bool passive) +{ + unsigned long currentMillis; + unsigned char n; + char prompted; + char buffer[OBD_RECV_BUF_SIZE]; + + for (unsigned char i = 0; i < INIT_CMD_COUNT; i++) { + if (!passive) { + char cmd[MAX_CMD_LEN]; + strcpy_P(cmd, s_initcmd[i]); + WriteData(cmd); + } + n = 0; + prompted = 0; + currentMillis = millis(); + for (;;) { + if (DataAvailable()) { + char c = ReadData(); + if (c == '>') { + buffer[n] = 0; + prompted++; + } else if (n < OBD_RECV_BUF_SIZE - 1) { + buffer[n++] = c; + } + } else if (prompted) { + break; + } else { + unsigned long elapsed = millis() - currentMillis; + if (elapsed > OBD_TIMEOUT_INIT) { + // init timeout + //WriteData("\r"); + return false; + } + } + } + } + errors = 0; + return true; +} diff --git a/libraries/OBD/OBD.h b/libraries/OBD/OBD.h new file mode 100644 index 0000000..1247c49 --- /dev/null +++ b/libraries/OBD/OBD.h @@ -0,0 +1,84 @@ +/************************************************************************* +* OBD-II (ELM327) data accessing library for Arduino +* Distributed under GPL v2.0 +* Copyright (c) 2012 Stanley Huang +* All rights reserved. +*************************************************************************/ + +#define OBD_TIMEOUT_SHORT 2000 /* ms */ +#define OBD_TIMEOUT_LONG 7000 /* ms */ +#define OBD_TIMEOUT_INIT 3000 /* ms */ +#define OBD_SERIAL_BAUDRATE 38400 +#define OBD_RECV_BUF_SIZE 48 + +#ifndef OBDUART +#ifdef __AVR_ATmega32U4__ /* for Leonardo */ +#define OBDUART Serial1 +#else +#define OBDUART Serial +#endif +#endif + +// mode 0 pids +#define PID_RPM 0x0C +#define PID_SPEED 0x0D +#define PID_THROTTLE 0x11 +#define PID_ENGINE_LOAD 0x04 +#define PID_COOLANT_TEMP 0x05 +#define PID_INTAKE_TEMP 0x0F +#define PID_MAF_FLOW 0x10 +#define PID_ABS_ENGINE_LOAD 0x43 +#define PID_AMBIENT_TEMP 0x46 +#define PID_FUEL_PRESSURE 0x0A +#define PID_INTAKE_PRESSURE 0x0B +#define PID_BAROMETRIC 0x33 +#define PID_TIMING_ADVANCE 0x0E +#define PID_FUEL_LEVEL 0x2F +#define PID_RUNTIME 0x1F +#define PID_DISTANCE 0x31 + +unsigned int hex2uint16(const char *p); +unsigned char hex2uint8(const char *p); + +class COBD +{ +public: + COBD() + { + dataMode = 1; + errors = 0; + } + bool Init(bool passive = false); + bool ReadSensor(byte pid, int& result, bool passive = false); + void Sleep(int seconds); + // Query and GetResponse for advanced usage only + void Query(byte pid); + virtual char* GetResponse(byte pid, char* buffer); + virtual bool GetResponse(byte pid, int& result); + virtual bool GetResponsePassive(byte& pid, int& result); + virtual bool DataAvailable(); + byte dataMode; + byte errors; + //char recvBuf[OBD_RECV_BUF_SIZE]; +protected: + static bool GetParsedData(byte pid, char* data, int& result); + static int GetPercentageValue(char* data) + { + return (int)hex2uint8(data) * 100 / 255; + } + static int GetLargeValue(char* data) + { + return hex2uint16(data); + } + static int GetSmallValue(char* data) + { + return hex2uint8(data); + } + static int GetTemperatureValue(char* data) + { + return (int)hex2uint8(data) - 40; + } + virtual char ReadData(); + virtual void WriteData(const char* s); + virtual void WriteData(const char c); +}; -- cgit v1.2.3