Enable pulseIn() (#140)

* Add files via upload

enable pulseIn()

* Remove optimistic_yield

cores/esp32/Arduino.h

@@ -133,6 +133,9 @@ void initArduino(void);
 void setup(void);
 void loop(void);
 
+unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout);
+unsigned long pulseInLong(uint8_t pin, uint8_t state, unsigned long timeout);
+
 uint8_t shiftIn(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder);
 void shiftOut(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t val);
 
@@ -156,6 +159,9 @@ uint16_t makeWord(byte h, byte l);
 
 #define word(...) makeWord(__VA_ARGS__)
 
+unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout = 1000000L);
+unsigned long pulseInLong(uint8_t pin, uint8_t state, unsigned long timeout = 1000000L);
+
 // WMath prototypes
 long random(long);
 #endif /* __cplusplus */

cores/esp32/wiring_pulse.c

+/*
+  pulse.c - wiring pulseIn implementation for esp8266
+  Copyright (c) 2015 Hristo Gochkov. All rights reserved.
+  This file is part of the esp8266 core for Arduino environment.
+  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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+//#include <limits.h>
+#include "wiring_private.h"
+#include "pins_arduino.h"
+
+
+extern uint32_t xthal_get_ccount();
+
+#define WAIT_FOR_PIN_STATE(state) \
+    while (digitalRead(pin) != (state)) { \
+        if (xthal_get_ccount() - start_cycle_count > timeout_cycles) { \
+            return 0; \
+        } \
+    }
+
+// max timeout is 27 seconds at 160MHz clock and 54 seconds at 80MHz clock
+unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout)
+{
+    const uint32_t max_timeout_us = clockCyclesToMicroseconds(UINT_MAX);
+    if (timeout > max_timeout_us) {
+        timeout = max_timeout_us;
+    }
+    const uint32_t timeout_cycles = microsecondsToClockCycles(timeout);
+    const uint32_t start_cycle_count = xthal_get_ccount();
+    WAIT_FOR_PIN_STATE(!state);
+    WAIT_FOR_PIN_STATE(state);
+    const uint32_t pulse_start_cycle_count = xthal_get_ccount();
+    WAIT_FOR_PIN_STATE(!state);
+    return clockCyclesToMicroseconds(xthal_get_ccount() - pulse_start_cycle_count);
+}
+
+unsigned long pulseInLong(uint8_t pin, uint8_t state, unsigned long timeout)
+{
+    return pulseIn(pin, state, timeout);
+}