diff options
| author | David A. Mellis <d.mellis@arduino.cc> | 2008-11-08 21:31:12 +0000 |
|---|---|---|
| committer | David A. Mellis <d.mellis@arduino.cc> | 2008-11-08 21:31:12 +0000 |
| commit | 68e9d04f91aa26daa4e3c701002610f2352039fd (patch) | |
| tree | 662675e12d23fac04d8ec7310fc3f58337684796 | |
| parent | 80fc987a942fc1711b2d0858449834db9568fa07 (diff) | |
Waiting for pulse to start (rising or falling edge) to start timing.
| -rwxr-xr-x | cores/arduino/wiring_pulse.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/cores/arduino/wiring_pulse.c b/cores/arduino/wiring_pulse.c index 0157114..8f232f1 100755 --- a/cores/arduino/wiring_pulse.c +++ b/cores/arduino/wiring_pulse.c @@ -44,6 +44,11 @@ unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout) unsigned long numloops = 0; unsigned long maxloops = microsecondsToClockCycles(timeout) / 16; + // wait for any previous pulse to end + while ((*portInputRegister(port) & bit) == stateMask) + if (numloops++ == maxloops) + return 0; + // wait for the pulse to start while ((*portInputRegister(port) & bit) != stateMask) if (numloops++ == maxloops) |