circuitpython/esp8266/esponewire.c

100 lines
2.9 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2015-2016 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdint.h>
#include "etshal.h"
#include "user_interface.h"
#include "modpyb.h"
#include "esponewire.h"
#define TIMING_RESET1 (0)
#define TIMING_RESET2 (1)
#define TIMING_RESET3 (2)
#define TIMING_READ1 (3)
#define TIMING_READ2 (4)
#define TIMING_READ3 (5)
#define TIMING_WRITE1 (6)
#define TIMING_WRITE2 (7)
#define TIMING_WRITE3 (8)
uint16_t esp_onewire_timings[9] = {480, 40, 420, 5, 5, 40, 10, 50, 10};
static uint32_t disable_irq(void) {
ets_intr_lock();
return 0;
}
static void enable_irq(uint32_t i) {
ets_intr_unlock();
}
static void mp_hal_delay_us_no_irq(uint32_t us) {
uint32_t start = system_get_time();
while (system_get_time() - start < us) {
}
}
#define DELAY_US mp_hal_delay_us_no_irq
int esp_onewire_reset(uint pin) {
pin_set(pin, 0);
DELAY_US(esp_onewire_timings[TIMING_RESET1]);
uint32_t i = disable_irq();
pin_set(pin, 1);
DELAY_US(esp_onewire_timings[TIMING_RESET2]);
int status = !pin_get(pin);
enable_irq(i);
DELAY_US(esp_onewire_timings[TIMING_RESET3]);
return status;
}
int esp_onewire_readbit(uint pin) {
pin_set(pin, 1);
uint32_t i = disable_irq();
pin_set(pin, 0);
DELAY_US(esp_onewire_timings[TIMING_READ1]);
pin_set(pin, 1);
DELAY_US(esp_onewire_timings[TIMING_READ2]);
int value = pin_get(pin);
enable_irq(i);
DELAY_US(esp_onewire_timings[TIMING_READ3]);
return value;
}
void esp_onewire_writebit(uint pin, int value) {
uint32_t i = disable_irq();
pin_set(pin, 0);
DELAY_US(esp_onewire_timings[TIMING_WRITE1]);
if (value) {
pin_set(pin, 1);
}
DELAY_US(esp_onewire_timings[TIMING_WRITE2]);
pin_set(pin, 1);
DELAY_US(esp_onewire_timings[TIMING_WRITE3]);
enable_irq(i);
}