Version 0.3.0:

 - Added SAM (Arduino DUE) compatibility
 - Some timing fixes
 - Examples more correct (added volatile to variable used in ISR)

examples/uTimerLib_setInterval_s_example_led/uTimerLib_setInterval_s_example_led.ino

@@ -11,7 +11,7 @@
 
 
 
-bool status = 0;
+volatile bool status = 0;
 
 void timed_function() {
 	status = !status;

examples/uTimerLib_setInterval_us_example_led/uTimerLib_setInterval_us_example_led.ino

@@ -17,7 +17,7 @@
 
 
 
-bool status = 0;
+volatile bool status = 0;
 
 void timed_function() {
 	status = !status;

examples/uTimerLib_setTimeout_s_example_led/uTimerLib_setTimeout_s_example_led.ino

@@ -11,7 +11,7 @@
 
 
 
-bool status = 0;
+volatile bool status = 0;
 
 void timed_function() {
 	status = !status;

examples/uTimerLib_setTimeout_us_example_led/uTimerLib_setTimeout_us_example_led.ino

@@ -11,7 +11,7 @@
 
 
 
-bool status = 0;
+volatile bool status = 0;
 
 void timed_function() {
 	status = !status;

extras/data sources.txt

@@ -1,3 +1,9 @@
 AVR Timer2:
  - https://hetpro-store.com/TUTORIALES/arduino-timer/
  - https://playground.arduino.cc/Main/TimerPWMCheatsheet
+
+Arduino DUE (SAM):
+ - https://forum.arduino.cc/index.php?topic=130423.0
+ - http://2manyprojects.net/timer-interrupts
+
+

library.properties

@@ -1,5 +1,5 @@
 name=uTimerLib
-version=0.2.1
+version=0.3.0
 author=Naguissa <naguissa@foroelectro.net>
 maintainer=Naguissa <naguissa@foroelectro.net>
 sentence=Tiny and cross-device compatible timer library

src/uTimerLib.cpp

@@ -4,6 +4,7 @@
  * Timers used by microcontroller
  *	Atmel AVR:	Timer2 (3rd timer)
  *  STM32:		Timer3 (3rd timer)
+ *  SAM (Due):  TC3 (Timer1, channel 0)
  *
  * @copyright Naguissa
  * @author Naguissa
@@ -100,6 +101,9 @@ int uTimerLib::setTimeout_s(void (* cb)(), unsigned long int s) {
  * @param	unsigned long int	us		Desired timing in microseconds
  */
 void uTimerLib::_attachInterrupt_us(unsigned long int us) {
+	if (us == 0) { // Not valid
+		return;
+	}
 	#ifdef ARDUINO_ARCH_AVR
 		unsigned char CSMask = 0;
 		// For this notes, we asume 16MHz CPU. We recalculate 'us' if not:
@@ -126,23 +130,23 @@ void uTimerLib::_attachInterrupt_us(unsigned long int us) {
 		if (us >= 16384) {
 			CSMask = (1<<CS22) | (1<<CS21) | (1<<CS20);
 			_overflows = us / 16384;
-			_remaining = 256 - round((us % 16384) / 64);
+			_remaining = 256 - ((us % 16384) / 64 + 0.5); // + 0.5 is round for positive numbers
 		} else {
 			if (us >= 4096) {
 				CSMask = (1<<CS22) | (1<<CS21) | (1<<CS20);
-				_remaining = 256 - round(us / 64);
+				_remaining = 256 - (us / 64 + 0.5); // + 0.5 is round for positive numbers
 			} else if (us >= 2048) {
 				CSMask = (1<<CS22) | (1<<CS21);
-				_remaining = 256 - round(us / 16);
+				_remaining = 256 - (us / 16 + 0.5); // + 0.5 is round for positive numbers
 			} else if (us >= 1024) {
 				CSMask = (1<<CS22) | (1<<CS20);
-				_remaining = 256 - round(us / 8);
+				_remaining = 256 - (us / 8 + 0.5); // + 0.5 is round for positive numbers
 			} else if (us >= 512) {
 				CSMask = (1<<CS22);
-				_remaining = 256 - round(us / 4);
+				_remaining = 256 - (us / 4 + 0.5); // + 0.5 is round for positive numbers
 			} else if (us >= 128) {
 				CSMask = (1<<CS21) | (1<<CS20);
-				_remaining = 256 - round(us / 2);
+				_remaining = 256 - (us / 2 + 0.5); // + 0.5 is round for positive numbers
 			} else if (us >= 16) {
 				CSMask = (1<<CS21);
 				_remaining = 256 - us * 2;
@@ -163,6 +167,7 @@ void uTimerLib::_attachInterrupt_us(unsigned long int us) {
 		// Clean counter in normal operation, load remaining when overflows == 0
 		if (__overflows == 0) {
 			_loadRemaining();
+			_remaining = 0;
 		} else {
 			TCNT2 = 0;				// Clean timer count
 		}
@@ -188,6 +193,66 @@ void uTimerLib::_attachInterrupt_us(unsigned long int us) {
 	#endif
 
 
+
+	// SAM, Arduino Due
+	#ifdef ARDUINO_ARCH_SAM
+		/*
+		Prescalers: MCK/2, MCK/8, MCK/32, MCK/128
+		Base frequency: 84MHz
+
+		Available Timers:
+		ISR/IRQ	 TC	  Channel	Due pins
+		  TC0	TC0		0		2, 13
+		  TC1	TC0		1		60, 61
+		  TC2	TC0		2		58
+		  TC3	TC1		0		none
+		  TC4	TC1		1		none
+		  TC5	TC1		2		none
+		  TC6	TC2		0		4, 5
+		  TC7	TC2		1		3, 10
+		  TC8	TC2		2		11, 12
+
+		We will use TC1, as it has no associated pins. We will choose Channel 0, so ISR is TC3
+
+		REMEMBER! 32 bit counter!!!
+
+
+				Name				Prescaler	Freq	Base Delay		Overflow delay
+		TC_CMR_TCCLKS_TIMER_CLOCK1	  2		    42MHz   0,023809524us	102261126,913327104us, 102,261126913327104s
+		TC_CMR_TCCLKS_TIMER_CLOCK2	  8		  10.5MHz	0,095238095us	409044503,35834112us, 409,04450335834112s
+		TC_CMR_TCCLKS_TIMER_CLOCK3	 32		 2.625MHz	0,380952381us	1636178017,523809524us, 1636,178017523809524s
+		TC_CMR_TCCLKS_TIMER_CLOCK4	128		656.25KHz	1,523809524us	6544712070,913327104us, 6544,712070913327104s
+
+		For simplify things, we'll use always TC_CMR_TCCLKS_TIMER_CLOCK32,as has enougth resolution for us.
+
+
+		*/
+		if (us > 1636178017) {
+			__overflows = _overflows = us / 1636178017.523809524;
+			__remaining = _remaining = (us - (1636178017.523809524 * _overflows)) / 0.380952381 + 0.5; // +0.5 is same as round
+		} else {
+			__overflows = _overflows = 0;
+			__remaining = _remaining = (us / 0.380952381 + 0.5); // +0.5 is same as round
+		}
+		pmc_set_writeprotect(false); // Enable write
+		pmc_enable_periph_clk((uint32_t) TC3_IRQn); // Enable TC1 - channel 0 peripheral
+		TC_Configure(TC1, 0, TC_CMR_WAVE | TC_CMR_WAVSEL_UP_RC | TC_CMR_TCCLKS_TIMER_CLOCK3); // Configure clock; prescaler = 32
+
+		if (__overflows == 0) {
+			_loadRemaining();
+			_remaining = 0;
+		} else {
+			TC_SetRC(TC1, 0, 4294967295); // Int on last number
+		}
+
+		TC_Start(TC1, 0);
+		TC1->TC_CHANNEL[0].TC_IER = TC_IER_CPCS;
+		TC1->TC_CHANNEL[0].TC_IDR = ~TC_IER_CPCS;
+		NVIC_EnableIRQ(TC3_IRQn);
+	#endif
+
+
+
 }
 
 
@@ -199,6 +264,9 @@ void uTimerLib::_attachInterrupt_us(unsigned long int us) {
  * @param	unsigned long int	s		Desired timing in seconds
  */
 void uTimerLib::_attachInterrupt_s(unsigned long int s) {
+	if (s == 0) { // Not valid
+		return;
+	}
 	// Arduino AVR
 	#ifdef ARDUINO_ARCH_AVR
 		unsigned char CSMask = 0;
@@ -224,9 +292,9 @@ void uTimerLib::_attachInterrupt_s(unsigned long int s) {
 		// Anti-Overflow trick:
 		if (s > 16384) {
 			unsigned long int temp = floor(s / 16384) * 16384;
-			_remaining = 256 - round((((s - temp) * 1000000) % 16384) / 64);
+			_remaining = 256 - ((((s - temp) * 1000000) % 16384) / 64 + 0.5); // + 0.5 is round for positive numbers
 		} else {
-			_remaining = 256 - round(((s * 1000000) % 16384) / 64);
+			_remaining = 256 - (((s * 1000000) % 16384) / 64 + 0.5); // + 0.5 is round for positive numbers
 		}
 
 		__overflows = _overflows;
@@ -264,6 +332,43 @@ void uTimerLib::_attachInterrupt_s(unsigned long int s) {
 		Timer3.resume();
 	#endif
 
+
+	// SAM, Arduino Due
+	#ifdef ARDUINO_ARCH_SAM
+		/*
+
+		See _ms functions for detailed info; here only selected points
+
+				Name				Prescaler	Freq	Base Delay		Overflow delay
+		TC_CMR_TCCLKS_TIMER_CLOCK4	128		656.25KHz	1,523809524us	6544712070,913327104us, 6544,712070913327104s
+
+		For simplify things, we'll use always TC_CMR_TCCLKS_TIMER_CLOCK32,as has enougth resolution for us.
+		*/
+		if (s > 6544) {
+			__overflows = _overflows = s / 6544.712070913327104;
+			__remaining = _remaining = (s - (6544.712070913327104 * _overflows) / 0.000001523809524 + 0.5); // +0.5 is same as round
+		} else {
+			__overflows = _overflows = 0;
+			__remaining = _remaining = (s / 0.000001523809524 + 0.5); // +0.5 is same as round
+		}
+
+		pmc_set_writeprotect(false); // Enable write
+		//pmc_enable_periph_clk((uint32_t) TC3_IRQn); // Enable TC1 - channel 0 peripheral
+		pmc_enable_periph_clk(ID_TC3); // Enable TC1 - channel 0 peripheral
+		TC_Configure(TC1, 0, TC_CMR_WAVE | TC_CMR_WAVSEL_UP_RC | TC_CMR_TCCLKS_TIMER_CLOCK4); // Configure clock; prescaler = 128
+
+		if (__overflows == 0) {
+			_loadRemaining();
+			_remaining = 0;
+		} else {
+			TC_SetRC(TC1, 0, 4294967295); // Int on last number
+		}
+
+		TC1->TC_CHANNEL[0].TC_IER=TC_IER_CPCS;
+		TC1->TC_CHANNEL[0].TC_IDR=~TC_IER_CPCS;
+		NVIC_EnableIRQ(TC3_IRQn);
+		TC_Start(TC1, 0);
+	#endif
 }
 
 
@@ -279,6 +384,10 @@ void uTimerLib::_loadRemaining() {
 	#endif
 
 	// STM32: Not needed
+
+	#ifdef ARDUINO_ARCH_SAM
+		TC_SetRC(TC1, 0, _remaining);
+	#endif
 }
 
 /**
@@ -297,6 +406,12 @@ void uTimerLib::clearTimer() {
 	#ifdef _VARIANT_ARDUINO_STM32_
 		Timer3.pause();
 	#endif
+
+	// SAM, Arduino Due
+	#ifdef ARDUINO_ARCH_SAM
+        NVIC_DisableIRQ(TC3_IRQn);
+	#endif
+
 }
 
 /**
@@ -309,27 +424,40 @@ void uTimerLib::_interrupt() {
 	if (_type == UTIMERLIB_TYPE_OFF) { // Should not happen
 		return;
 	}
+
 	if (_overflows > 0) {
 		_overflows--;
 	}
 	if (_overflows == 0 && _remaining > 0) {
-		// Load remaining count to counter
-		_loadRemaining();
-		// And clear remaining count
-		_remaining = 0;
+			// Load remaining count to counter
+			_loadRemaining();
+			// And clear remaining count
+			_remaining = 0;
 	} else if (_overflows == 0 && _remaining == 0) {
 		if (_type == UTIMERLIB_TYPE_TIMEOUT) {
 			clearTimer();
 		} else if (_type == UTIMERLIB_TYPE_INTERVAL) {
 			if (__overflows == 0) {
+				_remaining = __remaining;
 				_loadRemaining();
+				_remaining = 0;
 			} else {
 				_overflows = __overflows;
 				_remaining = __remaining;
+				#ifdef ARDUINO_ARCH_SAM
+					TC_SetRC(TC1, 0, 4294967295);
+				#endif
 			}
 		}
 		_cb();
 	}
+	#ifdef ARDUINO_ARCH_SAM
+		// Reload for SAM
+		else if (_overflows > 0) {
+			TC_SetRC(TC1, 0, 4294967295);
+		}
+	#endif
+
 }
 
 /**
@@ -361,3 +489,11 @@ uTimerLib TimerLib = uTimerLib();
 	}
 #endif
 
+
+#ifdef ARDUINO_ARCH_SAM
+	void TC3_Handler() {
+		TC_GetStatus(TC1, 0); // reset interrupt
+		TimerLib._interrupt();
+	}
+#endif
+

src/uTimerLib.h

@@ -48,9 +48,14 @@
 			static uTimerLib *_instance;
 
 			unsigned long int _overflows = 0;
-			unsigned char _remaining = 0;
 			unsigned long int __overflows = 0;
-			unsigned char __remaining = 0;
+			#ifdef ARDUINO_ARCH_AVR
+				unsigned char _remaining = 0;
+				unsigned char __remaining = 0;
+			#else
+				unsigned long int _remaining = 0;
+				unsigned long int __remaining = 0;
+			#endif
 			void (*_cb)() = NULL;
 			unsigned char _type = UTIMERLIB_TYPE_OFF;