SAM: fix pulseInLong timeout using micros()

Author: facchinm

cores/arduino/wiring_pulse.cpp

@@ -69,24 +69,22 @@ uint32_t pulseInLong(uint8_t pin, uint8_t state, unsigned long timeout)
 uint32_t bit = p.ulPin;
 uint32_t stateMask = state ? bit : 0;
 
-// convert the timeout from microseconds to a number of times through
-// the initial loop; it takes 18 clock cycles per iteration.
-unsigned long maxloops = microsecondsToClockCycles(timeout) / 10;
+unsigned long maxMicros = micros() + timeout;
 
 // wait for any previous pulse to end
 while ((p.pPort->PIO_PDSR & bit) == stateMask)
-if (--maxloops == 0)
+if (micros() > maxMicros)
 return 0;
 
 // wait for the pulse to start
 while ((p.pPort->PIO_PDSR & bit) != stateMask)
-if (--maxloops == 0)
+if (micros() > maxMicros)
 return 0;
 
 unsigned long start = micros();
 // wait for the pulse to stop
 while ((p.pPort->PIO_PDSR & bit) == stateMask) {
-if (--maxloops == 0)
+if (micros() > maxMicros)
 return 0;
 }
 return micros() - start;