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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 pulse.c - wiring pulseIn implementation for esp8266
Copyright (c) 2015 Hristo Gochkov. All rights reserved. Copyright (c) 2015 Hristo Gochkov. All rights reserved.
This file is part of the esp8266 core for Arduino environment. This file is part of the esp8266 core for Arduino environment.
This library is free software; you can redistribute it and/or This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either 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 License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/ */
#include <limits.h>
#include "wiring_private.h" #include "wiring_private.h"
#include "pins_arduino.h" #include "pins_arduino.h"
unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout) {
pinMode(pin, INPUT); extern uint32_t xthal_get_ccount();
uint32_t start = micros();
while(digitalRead(pin) == state && (micros() - start) < timeout); #define WAIT_FOR_PIN_STATE(state) \
while(digitalRead(pin) != state && (micros() - start) < timeout); while (digitalRead(pin) != (state)) { \
start = micros(); if (xthal_get_ccount() - start_cycle_count > timeout_cycles) { \
while(digitalRead(pin) == state && (micros() - start) < timeout); return 0; \
return micros() - start; } \
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); return pulseIn(pin, state, timeout);
} }