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Merge pull request #1768 from esp8266/pulsein_fix

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Fix pulseIn
This commit is contained in:
Ivan Grokhotkov 2016-03-30 21:10:06 +03:00
commit 2e849e30d2
1 changed files with 30 additions and 11 deletions
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41
cores/esp8266/core_esp8266_wiring_pulse.c
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@ -1,9 +1,9 @@
/*
/*
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
@ -18,19 +18,38 @@
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"
unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout) {
pinMode(pin, INPUT);
uint32_t start = micros();
while(digitalRead(pin) == state && (micros() - start) < timeout);
while(digitalRead(pin) != state && (micros() - start) < timeout);
start = micros();
while(digitalRead(pin) == state && (micros() - start) < timeout);
return micros() - start;
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; \
} \
optimistic_yield(5000); \
}
// 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) {
unsigned long pulseInLong(uint8_t pin, uint8_t state, unsigned long timeout)
{
return pulseIn(pin, state, timeout);
}