51 lines
2.0 KiB
C
51 lines
2.0 KiB
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);
|
||
|
|
}
|