move register-access to LowLevel.h, add support for ATtiny85

LowLevel.h

@@ -21,6 +21,43 @@
 #define DIRECT_WRITE_LOW(base, mask)    ((*((base)+2)) &= ~(mask))
 #define DIRECT_WRITE_HIGH(base, mask)   ((*((base)+2)) |= (mask))
 
+#if defined (__AVR_ATtiny85__)
+#define CLEARINTERRUPT GIFR |= (1 << INTF0)
+#include "UserTimer.h" //ATtiny-support based on TinyCore1 Arduino-core for ATtiny at http://github.com/Coding-Badly/TinyCore1.git
+__attribute__((always_inline)) static inline void UserTimer_Init( void )
+{
+	UserTimer_SetToPowerup();
+	UserTimer_SetWaveformGenerationMode(UserTimer_(CTC_OCR));
+}
+__attribute__((always_inline)) static inline void UserTimer_Run(short skipTicks)
+{
+	UserTimer_SetCount(0);
+	UserTimer_SetOutputCompareMatchAndClear(skipTicks);
+	UserTimer_ClockSelect(UserTimer_(Prescale_Value_64));
+}
+#define UserTimer_Stop() UserTimer_ClockSelect(UserTimer_(Stopped))
+
+#elif defined (__AVR_ATmega328P__)
+#define CLEARINTERRUPT EIFR |= (1 << INTF0)
+#define USERTIMER_COMPA_vect TIMER1_COMPA_vect
+
+__attribute__((always_inline)) static inline void UserTimer_Init( void )
+{
+	TCCR1A = 0;
+	TCCR1B = 0;
+	// enable timer compare interrupt
+	TIMSK1 |= (1 << OCIE1A);
+}
+__attribute__((always_inline)) static inline void UserTimer_Run(short skipTicks)
+{
+	TCNT1 = 0;
+	OCR1A = skipTicks;
+	// turn on CTC mode with 64 prescaler
+	TCCR1B = (1 << WGM12) | (1 << CS11) | (1 << CS10);
+}
+#define UserTimer_Stop() TCCR1B = 0
+#endif
+
 #elif defined(__MK20DX128__) || defined(__MK20DX256__)
 #define PIN_TO_BASEREG(pin)             (portOutputRegister(pin))
 #define PIN_TO_BITMASK(pin)             (1)
@@ -110,7 +147,7 @@ public:
 
 	inline void attachInterrupt(void (*handler)(), int mode)
 	{
-		EIFR |= (1 << INTF0); // clear any pending interrupt (we want to call the handler only for interrupts happending after it is attached)
+		CLEARINTERRUPT;  // clear any pending interrupt (we want to call the handler only for interrupts happending after it is attached)
 		::attachInterrupt(interruptNumber_, handler, mode);
 	}
 	inline void detachInterrupt() { ::detachInterrupt(interruptNumber_); }

OneWireSlave.cpp

@@ -31,7 +31,6 @@ OneWireSlave OWSlave;
 byte OneWireSlave::rom_[8];
 byte OneWireSlave::scratchpad_[8];
 Pin OneWireSlave::pin_;
-byte OneWireSlave::tccr1bEnable_;
 
 unsigned long OneWireSlave::resetStart_;
 unsigned long OneWireSlave::lastReset_;
@@ -62,9 +61,9 @@ bool OneWireSlave::singleBitRepeat_;
 void(*OneWireSlave::singleBitSentCallback_)(bool error);
 
 
-ISR(TIMER1_COMPA_vect) // timer1 interrupt
+ISR(USERTIMER_COMPA_vect) // timer1 interrupt
 {
-	TCCR1B = 0; // disable clock
+	UserTimer_Stop(); // disable clock
 	void(*event)() = timerEvent;
 	timerEvent = 0;
 	event();
@@ -91,10 +90,7 @@ void OneWireSlave::begin(const byte* rom, byte pinNumber)
 	pin_.writeLow(); // make sure the internal pull-up resistor is disabled
 
 	// prepare hardware timer
-	TCCR1A = 0;
+	UserTimer_Init();
-	TCCR1B = 0;
-	TIMSK1 |= (1 << OCIE1A); // enable timer compare interrupt
-	tccr1bEnable_ = (1 << WGM12) | (1 << CS11) | (1 << CS10); // turn on CTC mode with 64 prescaler
 
 	// start 1-wire activity
 	beginWaitReset_();
@@ -178,15 +174,13 @@ void OneWireSlave::setTimerEvent_(short delayMicroSeconds, void(*handler)())
 
 	short skipTicks = (delayMicroSeconds - 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;
-	TCNT1 = 0;
-	OCR1A = skipTicks;
 	timerEvent = handler;
-	TCCR1B = tccr1bEnable_;
+	UserTimer_Run(skipTicks);
 }
 
 void OneWireSlave::disableTimer_()
 {
-	TCCR1B = 0;
+	UserTimer_Stop();
 }
 
 void OneWireSlave::onEnterInterrupt_()

OneWireSlave.h

@@ -91,7 +91,6 @@ private:
 	static byte rom_[8];
 	static byte scratchpad_[8];
 	static Pin pin_;
-	static byte tccr1bEnable_;
 
 	static unsigned long resetStart_;
 	static unsigned long lastReset_;