implemented presence with timer interrupts

OneWireIO.ino

@@ -10,39 +10,67 @@
 #define ResetMaxDuration 900
 
 #define PresenceWaitDuration 30
-#define PresenceDuration 150
+#define PresenceDuration 300
 
 SerialChannel debug("debug");
 
 Pin owPin(OWPin);
-Pin ledPin(LEDPin);
+Pin owOutTestPin(3);
+Pin led(LEDPin);
 
-unsigned long resetStart = (unsigned long)-1;
+void owPullLow()
+{
+	owPin.outputMode();
+	owPin.writeLow();
+	owOutTestPin.writeLow();
+}
+
+void owRelease()
+{
+	owPin.inputMode();
+	owOutTestPin.writeHigh();
+}
 
-enum Status
+void owWrite(bool value)
 {
-	S_WaitReset,
-	S_WaitPresence,
-	S_Presence,
-};
+	if (value)
+		owRelease();
+	else
+		owPullLow();
+}
 
-Status status = S_WaitReset;
-unsigned long statusChangeTime = (unsigned long)-1;
+unsigned long resetStart = (unsigned long)-1;
 
 void setup()
 {
-	ledPin.outputMode();
+	led.outputMode();
 	owPin.inputMode();
+	owOutTestPin.outputMode();
+	owOutTestPin.writeHigh();
 
-	ledPin.writeLow();
+	led.writeLow();
 
+	cli(); // disable interrupts
     attachInterrupt(InterruptNumber,onewireInterrupt,CHANGE);
 
+	// set timer0 interrupt at 250KHz (actually depends on compare match register OCR0A)
+	// 4us between each tick
+	TCCR1A = 0;
+	TCCR1B = 0;
+	TCNT1 = 0; // initialize counter value to 0
+	//TCCR1B |= (1 << WGM12); // turn on CTC mode
+	//TCCR1B |= (1 << CS11) | (1 << CS10); // Set 64 prescaler
+	TIMSK1 |= (1 << OCIE1A); // enable timer compare interrupt
+	sei(); // enable interrupts
+    
     Serial.begin(400000);
 }
 
+//int count = 0;
 void loop()
 {
+	//if ((count++) % 1000 == 0)
+	//	led.write(!led.read());
     cli();//disable interrupts
 	SerialChannel::swap();
     sei();//enable interrupts
@@ -50,12 +78,26 @@ void loop()
 	SerialChannel::flush();
 }
 
+void(*timerEvent)() = 0;
+void setTimerEvent(short microSecondsDelay, void(*event)())
+{
+	microSecondsDelay -= 10; // this seems to be the typical time taken to initialize the timer on Arduino Uno
+
+	short skipTicks = (microSecondsDelay - 3) / 4; // round the micro seconds delay to a number of ticks to skip (4us per tick, so 4us must skip 0 tick, 8us must skip 1 tick, etc.)
+	if (skipTicks < 1) skipTicks = 1;
+	//debug.SC_APPEND_STR_INT("setTimerEvent", (long)skipTicks);
+	TCNT1 = 0;
+	OCR1A = skipTicks;
+	timerEvent = event;
+	TCCR1B = (1 << WGM12) | (1 << CS11) | (1 << CS10); // turn on CTC mode with 64 prescaler
+}
+
 void onewireInterrupt(void)
 {
 	bool state = owPin.read();
 	unsigned long now = micros();
 
-	//ledPin.write(state);
+	//led.write(state);
 
 	if (!state)
 		resetStart = now;
@@ -67,10 +109,32 @@ void onewireInterrupt(void)
 
 		if (resetDuration >= ResetMinDuration && resetDuration <= ResetMaxDuration)
 		{
-			debug.SC_APPEND_STR_TIME("reset", now);
-			status = S_WaitPresence;
-			statusChangeTime = now;
+			//debug.SC_APPEND_STR_TIME("reset", now);
+			setTimerEvent(PresenceWaitDuration - (micros() - now), &beginPresence);
 			return;
 		}
 	}
 }
+
+void beginPresence()
+{
+	//debug.SC_APPEND_STR("beginPresence");
+	owPullLow();
+	owOutTestPin.writeLow();
+	setTimerEvent(PresenceDuration, &endPresence);
+}
+
+void endPresence()
+{
+	//debug.SC_APPEND_STR("endPresence");
+	owRelease();
+}
+
+ISR(TIMER1_COMPA_vect) // timer1 interrupt
+{
+	TCCR1B = 0; // disable clock
+	void(*event)() = timerEvent;
+	timerEvent = 0;
+	if (event != 0)
+		event();
+}

OneWireIO.vcxproj

@@ -44,8 +44,8 @@
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
       <SDLCheck>true</SDLCheck>
-      <AdditionalIncludeDirectories>D:\Outils\Arduino\hardware\arduino\avr\cores\arduino</AdditionalIncludeDirectories>
-      <PreprocessorDefinitions>_MBCS;%(PreprocessorDefinitions);ARDUINO=160;__AVR__</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>D:\Outils\Arduino\hardware\arduino\avr\cores\arduino;D:\Outils\Arduino\hardware\tools\avr\avr\include</AdditionalIncludeDirectories>
+      <PreprocessorDefinitions>_MBCS;%(PreprocessorDefinitions);ARDUINO=160;__AVR__;UBRRH;__AVR_ATmega328__</PreprocessorDefinitions>
     </ClCompile>
     <Link>
       <GenerateDebugInformation>true</GenerateDebugInformation>
@@ -66,7 +66,9 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
-    <None Include="OneWireIO.ino" />
+    <None Include="OneWireIO.ino">
+      <FileType>Document</FileType>
+    </None>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="SerialChannel.cpp" />

OneWireIO.vcxproj.filters

@@ -1,8 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <ItemGroup>
-    <None Include="OneWireIO.ino" />
-  </ItemGroup>
   <ItemGroup>
     <ClCompile Include="SerialChannel.cpp" />
   </ItemGroup>
@@ -10,4 +7,7 @@
     <ClInclude Include="SerialChannel.h" />
     <ClInclude Include="LowLevel.h" />
   </ItemGroup>
+  <ItemGroup>
+    <None Include="OneWireIO.ino" />
+  </ItemGroup>
 </Project>

SerialChannel.cpp

@@ -61,7 +61,7 @@ void SerialChannel::write(const char* text, unsigned long time)
     write((byte*)text, strlen(text), time);
 }
 
-void SerialChannel::append(byte* data, short byteCount, unsigned long time)
+SerialChannel::Message& SerialChannel::append(byte* data, short byteCount, unsigned long time)
 {
 	if (time == (unsigned long)-1)
 		time = micros();
@@ -73,6 +73,9 @@ void SerialChannel::append(byte* data, short byteCount, unsigned long time)
 	msg.data = data;
 	msg.byteCount = byteCount;
 	msg.time = time;
+	msg.longArg0 = 0;
+
+	return msg;
 }
 
 void SerialChannel::append(const char* text, unsigned long time)
@@ -80,6 +83,12 @@ void SerialChannel::append(const char* text, unsigned long time)
 	append((byte*)text, strlen(text), time);
 }
 
+void SerialChannel::appendInt(const char* text, short textLength, int arg0, unsigned long time)
+{
+	Message& msg = append((byte*)text, textLength, time);
+	msg.longArg0 = arg0 | 0x40000000;
+}
+
 void SerialChannel::swap()
 {
 	backBuffer = backBuffer == buffer1 ? buffer2 : buffer1;
@@ -94,9 +103,21 @@ void SerialChannel::flush()
 	Message* frontBuffer = backBuffer == buffer1 ? buffer2 : buffer1;
 	for (Message* msg = frontBuffer; msg < frontBuffer + frontBufferSize; ++msg)
 	{
-		beginWriteInChannel(msg->id, msg->byteCount, msg->time);
+		char params[32];
+		params[0] = 0;
+
+		if ((msg->longArg0 & 0x40000000) != 0)
+			sprintf(params, ";arg0=%ld", msg->longArg0 & ~0x40000000);
+
+		short paramsSize = strlen(params);
+
+		beginWriteInChannel(msg->id, msg->byteCount + paramsSize, msg->time);
 		Serial.write(msg->data, msg->byteCount);
+		if (paramsSize > 0)
+			Serial.write(params, paramsSize);
 	}
+
+	Serial.flush();
 }
 
 void SerialChannel::writeShort(short num)

SerialChannel.h

@@ -2,6 +2,8 @@
 #define _SerialChannel_h_
 
 #define SC_APPEND_STR(str) append((byte*)str, sizeof(str)-1)
+#define SC_APPEND_STR_INT(str, arg0) appendInt(str, sizeof(str)-1, arg0)
+
 #define SC_APPEND_STR_TIME(str, time) append((byte*)str, sizeof(str)-1, time)
 
 class SerialChannel
@@ -11,8 +13,9 @@ private:
 
 	struct Message
 	{
-		byte* data;
 		unsigned long time;
+		long longArg0;
+		byte* data;
 		short byteCount;
 		byte id;
 	};
@@ -40,8 +43,9 @@ public:
 	void beginWrite(short byteCount, unsigned long time = (unsigned long)-1);
 	void continueWrite(byte* data, short byteCount);
 
-	void append(byte* data, short byteCount, unsigned long time = (unsigned long)-1);
+	Message& append(byte* data, short byteCount, unsigned long time = (unsigned long)-1);
 	void append(const char* text, unsigned long time = (unsigned long)-1);
+	void appendInt(const char* text, short textLength, int arg0, unsigned long time = (unsigned long)-1);
 	static void swap();
 	static void flush();
     

SerialMonitor/SerialMonitor/App.xaml.cs

@@ -33,13 +33,13 @@ namespace SerialMonitor
             Serial.DataReceived += new System.IO.Ports.SerialDataReceivedEventHandler(OnDataReceived);
 
             Serial.Open();
+            Serial.Write("C");
         }
 
         private void OnDataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
         {
             if (!Connected)
             {
-                Serial.Write("C");
                 Serial.ReadTo("CONNECTION");
                 Connected = true;
             }