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pulseIn() now times out while measuring the pulse, not just while waiting for it to start.

This commit is contained in:
David A. Mellis 2010-11-22 23:33:59 -05:00
parent 9e183cb0b4
commit b9c749547a
1 changed files with 6 additions and 3 deletions
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9
cores/arduino/wiring_pulse.c
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@ -55,12 +55,15 @@ unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout)
return 0; return 0;
// wait for the pulse to stop // wait for the pulse to stop
while ((*portInputRegister(port) & bit) == stateMask) while ((*portInputRegister(port) & bit) == stateMask) {
if (numloops++ == maxloops)
return 0;
width++; width++;
}
// convert the reading to microseconds. The loop has been determined // convert the reading to microseconds. The loop has been determined
// to be 10 clock cycles long and have about 16 clocks between the edge // 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 // and the start of the loop. There will be some error introduced by
// the interrupt handlers. // the interrupt handlers.
return clockCyclesToMicroseconds(width * 10 + 16); return clockCyclesToMicroseconds(width * 21 + 16);
} }