diff options
Diffstat (limited to 'cores/arduino/wiring_pulse.c')
| -rw-r--r-- | cores/arduino/wiring_pulse.c | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/cores/arduino/wiring_pulse.c b/cores/arduino/wiring_pulse.c index 4da446c..4c44d1c 100644 --- a/cores/arduino/wiring_pulse.c +++ b/cores/arduino/wiring_pulse.c @@ -40,16 +40,14 @@ unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout) uint8_t bit = digitalPinToBitMask(pin); uint8_t port = digitalPinToPort(pin); uint8_t stateMask = (state ? bit : 0); - unsigned long width = 0; // keep initialization out of time critical area // convert the timeout from microseconds to a number of times through // the initial loop; it takes approximately 16 clock cycles per iteration - unsigned long numloops = 0; unsigned long maxloops = microsecondsToClockCycles(timeout)/16; - width = countPulseASM(portInputRegister(port), bit, stateMask, maxloops); + unsigned long width = countPulseASM(portInputRegister(port), bit, stateMask, maxloops); - //prevent clockCyclesToMicroseconds to return bogus values if countPulseASM timed out + // prevent clockCyclesToMicroseconds to return bogus values if countPulseASM timed out if (width) return clockCyclesToMicroseconds(width * 16 + 16); else @@ -72,7 +70,6 @@ unsigned long pulseInLong(uint8_t pin, uint8_t state, unsigned long timeout) uint8_t bit = digitalPinToBitMask(pin); uint8_t port = digitalPinToPort(pin); uint8_t stateMask = (state ? bit : 0); - unsigned long width = 0; // keep initialization out of time critical area // convert the timeout from microseconds to a number of times through // the initial loop; it takes 16 clock cycles per iteration. @@ -89,11 +86,11 @@ unsigned long pulseInLong(uint8_t pin, uint8_t state, unsigned long timeout) if (numloops++ == maxloops) return 0; - unsigned long start = micros(); - // wait for the pulse to stop - while ((*portInputRegister(port) & bit) == stateMask) { - if (numloops++ == maxloops) - return 0; - } - return micros() - start; + unsigned long start = micros(); + // wait for the pulse to stop + while ((*portInputRegister(port) & bit) == stateMask) { + if (numloops++ == maxloops) + return 0; + } + return micros() - start; } |