From eb9c51d43c451b3e48725d04af519d8a6c36107b Mon Sep 17 00:00:00 2001 From: "David A. Mellis" Date: Mon, 22 Nov 2010 23:33:59 -0500 Subject: [PATCH] pulseIn() now times out while measuring the pulse, not just while waiting for it to start. --- cores/arduino/wiring_pulse.c | 9 ++++++--- 1 file 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); }