initial commit

2 files changed, 353 insertions, 0 deletions

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 <stanleyhuangyc@gmail.com>
+* All rights reserved.
+*************************************************************************/
+
+#include <Arduino.h>
+#include <avr/pgmspace.h>
+#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 <stanleyhuangyc@gmail.com>
+* 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);
+};