improving OBD-II library, adding IsValidPID API

2 files changed, 42 insertions, 19 deletions

diff --git a/libraries/OBD/OBD.cpp b/libraries/OBD/OBD.cpp
index 938523b..5ea4c47 100644
--- a/libraries/OBD/OBD.cpp
+++ b/libraries/OBD/OBD.cpp
@@ -9,13 +9,14 @@
 #include <avr/pgmspace.h>
 #include "OBD.h"
 
-#define INIT_CMD_COUNT 7
+#define INIT_CMD_COUNT 4
 #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_initcmd[INIT_CMD_COUNT][MAX_CMD_LEN] = {"ATZ\r","ATE0\r","ATL1\r","ATI\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_cmd_sleep[] = "atlp\r";
+const char PROGMEM s_cmd_vin[] = "0902\r";
 const char PROGMEM s_response_begin[] = "41 ";
 
 unsigned int hex2uint16(const char *p)
@@ -176,7 +177,7 @@ bool COBD::GetParsedData(byte pid, char* data, int& result)
 		break;
 	case PID_SPEED:
 	case PID_BAROMETRIC:
-	case PID_INTAKE_PRESSURE:
+	case PID_INTAKE_MAP:
 		result = GetSmallValue(data);
 		break;
 	case PID_TIMING_ADVANCE:
@@ -227,6 +228,16 @@ void COBD::Sleep(int seconds)
     }
 }
 
+bool COBD::IsValidPID(byte pid)
+{
+    if (pid >= 0x7f)
+        return false;
+    pid--;
+    byte i = pid >> 3;
+    byte b = 0x80 >> (pid & 0x7);
+    return pidmap[i] & b;
+}
+
 bool COBD::Init(bool passive)
 {
 	unsigned long currentMillis;
@@ -265,6 +276,20 @@ bool COBD::Init(bool passive)
             }
         }
     }
+
+    // load pid map
+    memset(pidmap, 0, sizeof(pidmap));
+    for (byte i = 0; i < 4; i++) {
+        Query(i * 0x20);
+        char* data = GetResponse(i * 0x20, buffer);
+        if (!data) break;
+        data--;
+        for (byte n = 0; n < 4; n++) {
+            if (data[n * 3] != ' ')
+                break;
+            pidmap[i * 4 + n] = hex2uint8(data + n * 3 + 1);
+        }
+    }
     errors = 0;
 	return true;
 }
diff --git a/libraries/OBD/OBD.h b/libraries/OBD/OBD.h
index e608fee..acc6735 100644
--- a/libraries/OBD/OBD.h
+++ b/libraries/OBD/OBD.h
@@ -1,7 +1,8 @@
 /*************************************************************************
-* OBD-II (ELM327) data accessing library for Arduino
+* Arduino OBD-II UART Adapter Library
+* http://www.arduinodev.com/hardware/obd-kit
 * Distributed under GPL v2.0
-* Copyright (c) 2012 Stanley Huang <stanleyhuangyc@gmail.com>
+* (C)2012~2013 Written by Stanley Huang <stanleyhuangyc@gmail.com>
 * All rights reserved.
 *************************************************************************/
 
@@ -9,7 +10,7 @@
 #define OBD_TIMEOUT_LONG 7000 /* ms */
 #define OBD_TIMEOUT_INIT 3000 /* ms */
 #define OBD_SERIAL_BAUDRATE 38400
-#define OBD_RECV_BUF_SIZE 48
+#define OBD_RECV_BUF_SIZE 64
 
 #ifndef OBDUART
 #ifdef __AVR_ATmega32U4__ /* for Leonardo */
@@ -30,7 +31,7 @@
 #define PID_ABS_ENGINE_LOAD 0x43
 #define PID_AMBIENT_TEMP 0x46
 #define PID_FUEL_PRESSURE 0x0A
-#define PID_INTAKE_PRESSURE 0x0B
+#define PID_INTAKE_MAP 0x0B
 #define PID_BAROMETRIC 0x33
 #define PID_TIMING_ADVANCE 0x0E
 #define PID_FUEL_LEVEL 0x2F
@@ -43,25 +44,24 @@ unsigned char hex2uint8(const char *p);
 class COBD
 {
 public:
-    COBD()
-    {
-        dataMode = 1;
-        errors = 0;
-    }
+    COBD():dataMode(1),errors(0) {}
 	bool Init(bool passive = false);
 	bool ReadSensor(byte pid, int& result, bool passive = false);
+	bool IsValidPID(byte pid);
 	void Sleep(int seconds);
-	// Query and GetResponse for advanced usage only
+	// following APIs are for advanced usages only
 	void Query(byte pid);
+    bool GetParsedData(byte pid, char* data, int& result);
 	virtual char* GetResponse(byte pid, char* buffer);
 	virtual bool GetResponse(byte pid, int& result);
 	virtual bool GetResponsePassive(byte& pid, int& result);
 	virtual bool DataAvailable();
+	virtual char ReadData();
+	virtual void WriteData(const char* s);
+	virtual void WriteData(const char c);
 	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;
@@ -78,8 +78,6 @@ protected:
 	{
 		return (int)hex2uint8(data) - 40;
 	}
-	virtual char ReadData();
-	virtual void WriteData(const char* s);
-	virtual void WriteData(const char c);
 	virtual void DataTimeout() {}
+	byte pidmap[4 * 4];
 };