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authorHampusM <hampus@hampusmat.com>2022-03-07 13:48:57 +0100
committerHampusM <hampus@hampusmat.com>2022-03-07 13:48:57 +0100
commit563f69b870a7f71026c50605b531ed40d667b0a2 (patch)
treef9dd8374cae6affb3b52d79e22823c78187b99ed /cores/xinput/wiring_pulse.c
parentf4a2dc0440d17e4c9e609e01e12fcd786d268cf7 (diff)
rename arduino core dir to xinputHEADmaster
Diffstat (limited to 'cores/xinput/wiring_pulse.c')
-rw-r--r--cores/xinput/wiring_pulse.c93
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;
+}