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Fixing bug in calling micros() from interrupts: http://code.google.com/p/arduino/issues/detail?id=55

This commit is contained in:
David A. Mellis 2009-12-18 17:44:08 +00:00
parent ba5935e273
commit 3063c34ebe

View File

@ -75,21 +75,21 @@ unsigned long millis()
} }
unsigned long micros() { unsigned long micros() {
unsigned long m, t; unsigned long m;
uint8_t oldSREG = SREG; uint8_t oldSREG = SREG, t;
cli(); cli();
m = timer0_overflow_count;
t = TCNT0; t = TCNT0;
#ifdef TIFR0 #ifdef TIFR0
if ((TIFR0 & _BV(TOV0)) && (t == 0)) if ((TIFR0 & _BV(TOV0)) && (t < 255))
t = 256; m++;
#else #else
if ((TIFR & _BV(TOV0)) && (t == 0)) if ((TIFR & _BV(TOV0)) && (t < 255))
t = 256; m++;
#endif #endif
m = timer0_overflow_count;
SREG = oldSREG; SREG = oldSREG;
return ((m << 8) + t) * (64 / clockCyclesPerMicrosecond()); return ((m << 8) + t) * (64 / clockCyclesPerMicrosecond());