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authorDavid A. Mellis <d.mellis@arduino.cc>2010-11-22 23:33:59 -0500
committerDavid A. Mellis <d.mellis@arduino.cc>2010-11-22 23:33:59 -0500
commiteb9c51d43c451b3e48725d04af519d8a6c36107b (patch)
treec3b55b5688d873b452b648e6a2cab9d17099e0ec /cores/arduino/wiring_pulse.c
parent6ac63fbadfd25eea9c1b4aa375c238df92ee23cb (diff)
pulseIn() now times out while measuring the pulse, not just while waiting for it to start.
Diffstat (limited to 'cores/arduino/wiring_pulse.c')
-rwxr-xr-xcores/arduino/wiring_pulse.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/cores/arduino/wiring_pulse.c b/cores/arduino/wiring_pulse.c
index 8f232f1..0d96886 100755
--- a/cores/arduino/wiring_pulse.c
+++ b/cores/arduino/wiring_pulse.c
@@ -55,12 +55,15 @@ unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout)
return 0;
// wait for the pulse to stop
- while ((*portInputRegister(port) & bit) == stateMask)
+ while ((*portInputRegister(port) & bit) == stateMask) {
+ if (numloops++ == maxloops)
+ return 0;
width++;
+ }
// 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
// the interrupt handlers.
- return clockCyclesToMicroseconds(width * 10 + 16);
+ return clockCyclesToMicroseconds(width * 21 + 16);
}