1 files changed, 93 insertions, 0 deletions
diff --git a/cores/xinput/wiring_pulse.c b/cores/xinput/wiring_pulse.c
new file mode 100644
index 0000000..d6e0434
--- /dev/null
+++ b/cores/xinput/wiring_pulse.c
@@ -0,0 +1,93 @@
+/*
+  wiring_pulse.c - pulseIn() function
+  Part of Arduino - http://www.arduino.cc/
+
+  Copyright (c) 2005-2006 David A. Mellis
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General
+  Public License along with this library; if not, write to the
+  Free Software Foundation, Inc., 59 Temple Place, Suite 330,
+  Boston, MA  02111-1307  USA
+*/
+
+#include "wiring_private.h"
+#include "pins_arduino.h"
+
+/* Measures the length (in microseconds) of a pulse on the pin; state is HIGH
+ * or LOW, the type of pulse to measure.  Works on pulses from 2-3 microseconds
+ * to 3 minutes in length, but must be called at least a few dozen microseconds
+ * before the start of the pulse.
+ *
+ * This function performs better with short pulses in noInterrupt() context
+ */
+unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout)
+{
+	// cache the port and bit of the pin in order to speed up the
+	// pulse width measuring loop and achieve finer resolution.  calling
+	// digitalRead() instead yields much coarser resolution.
+	uint8_t bit = digitalPinToBitMask(pin);
+	uint8_t port = digitalPinToPort(pin);
+	uint8_t stateMask = (state ? bit : 0);
+
+	// convert the timeout from microseconds to a number of times through
+	// the initial loop; it takes approximately 16 clock cycles per iteration
+	unsigned long maxloops = microsecondsToClockCycles(timeout)/16;
+
+	unsigned long width = countPulseASM(portInputRegister(port), bit, stateMask, maxloops);
+
+	// prevent clockCyclesToMicroseconds to return bogus values if countPulseASM timed out
+	if (width)
+		return clockCyclesToMicroseconds(width * 16 + 16);
+	else
+		return 0;
+}
+
+/* Measures the length (in microseconds) of a pulse on the pin; state is HIGH
+ * or LOW, the type of pulse to measure.  Works on pulses from 2-3 microseconds
+ * to 3 minutes in length, but must be called at least a few dozen microseconds
+ * before the start of the pulse.
+ *
+ * ATTENTION:
+ * this function relies on micros() so cannot be used in noInterrupt() context
+ */
+unsigned long pulseInLong(uint8_t pin, uint8_t state, unsigned long timeout)
+{
+	// cache the port and bit of the pin in order to speed up the
+	// pulse width measuring loop and achieve finer resolution.  calling
+	// digitalRead() instead yields much coarser resolution.
+	uint8_t bit = digitalPinToBitMask(pin);
+	uint8_t port = digitalPinToPort(pin);
+	uint8_t stateMask = (state ? bit : 0);
+
+	unsigned long startMicros = micros();
+
+	// wait for any previous pulse to end
+	while ((*portInputRegister(port) & bit) == stateMask) {
+		if (micros() - startMicros > timeout)
+			return 0;
+	}
+
+	// wait for the pulse to start
+	while ((*portInputRegister(port) & bit) != stateMask) {
+		if (micros() - startMicros > timeout)
+			return 0;
+	}
+
+	unsigned long start = micros();
+	// wait for the pulse to stop
+	while ((*portInputRegister(port) & bit) == stateMask) {
+		if (micros() - startMicros > timeout)
+			return 0;
+	}
+	return micros() - start;
+}