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Merge pull request #2556 from cmaglie/ide-1.5.x-pulsein-regression

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Temporary fix for pulseIn() regression
This commit is contained in:
Cristian Maglie 2015-01-19 13:40:09 +01:00
commit 07d1abfe43
1 changed files with 20 additions and 4 deletions
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24
hardware/arduino/avr/cores/arduino/wiring_pulse.c
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@ -61,9 +61,25 @@ unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout)
width++;
}
// convert the reading to microseconds. The loop has been determined
// to be 20 clock cycles long and have about 16 clocks between the edge
// and the start of the loop. There will be some error introduced by
// convert the reading to microseconds. There will be some error introduced by
// the interrupt handlers.
return clockCyclesToMicroseconds(width * 21 + 16);
// Conversion constants are compiler-dependent, different compiler versions
// have different levels of optimization.
#if __GNUC__==4 && __GNUC_MINOR__==3 && __GNUC_PATCHLEVEL__==2
// avr-gcc 4.3.2
return clockCyclesToMicroseconds(width * 21 + 16);
#elif __GNUC__==4 && __GNUC_MINOR__==8 && __GNUC_PATCHLEVEL__==1
// avr-gcc 4.8.1
return clockCyclesToMicroseconds(width * 24 + 16);
#elif __GNUC__<=4 && __GNUC_MINOR__<=3
// avr-gcc <=4.3.x
#warning "pulseIn() results may not be accurate"
return clockCyclesToMicroseconds(width * 21 + 16);
#else
// avr-gcc >4.3.x
#warning "pulseIn() results may not be accurate"
return clockCyclesToMicroseconds(width * 24 + 16);
#endif
}