95 lines
3.0 KiB
C
95 lines
3.0 KiB
C
/*
|
|
* This file is part of the MicroPython project, http://micropython.org/
|
|
*
|
|
* The MIT License (MIT)
|
|
*
|
|
* Copyright (c) 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 <stdio.h>
|
|
|
|
#include "py/runtime.h"
|
|
#include "py/mperrno.h"
|
|
#include "py/mphal.h"
|
|
#include "extmod/machine_pulse.h"
|
|
#include "drivers/dht/dht.h"
|
|
|
|
// Allow the open-drain-high call to be DHT specific for ports that need it
|
|
#ifndef mp_hal_pin_od_high_dht
|
|
#define mp_hal_pin_od_high_dht mp_hal_pin_od_high
|
|
#endif
|
|
|
|
STATIC mp_obj_t dht_readinto(mp_obj_t pin_in, mp_obj_t buf_in) {
|
|
mp_hal_pin_obj_t pin = mp_hal_get_pin_obj(pin_in);
|
|
mp_hal_pin_open_drain(pin);
|
|
|
|
mp_buffer_info_t bufinfo;
|
|
mp_get_buffer_raise(buf_in, &bufinfo, MP_BUFFER_WRITE);
|
|
|
|
if (bufinfo.len < 5) {
|
|
mp_raise_ValueError("buffer too small");
|
|
}
|
|
|
|
// issue start command
|
|
mp_hal_pin_od_high_dht(pin);
|
|
mp_hal_delay_ms(250);
|
|
mp_hal_pin_od_low(pin);
|
|
mp_hal_delay_ms(18);
|
|
|
|
mp_uint_t irq_state = mp_hal_quiet_timing_enter();
|
|
|
|
// release the line so the device can respond
|
|
mp_hal_pin_od_high_dht(pin);
|
|
mp_hal_delay_us_fast(10);
|
|
|
|
// wait for device to respond
|
|
mp_uint_t ticks = mp_hal_ticks_us();
|
|
while (mp_hal_pin_read(pin) != 0) {
|
|
if ((mp_uint_t)(mp_hal_ticks_us() - ticks) > 100) {
|
|
goto timeout;
|
|
}
|
|
}
|
|
|
|
// time pulse, should be 80us
|
|
ticks = machine_time_pulse_us(pin, 1, 150);
|
|
if ((mp_int_t)ticks < 0) {
|
|
goto timeout;
|
|
}
|
|
|
|
// time 40 pulses for data (either 26us or 70us)
|
|
uint8_t *buf = bufinfo.buf;
|
|
for (int i = 0; i < 40; ++i) {
|
|
ticks = machine_time_pulse_us(pin, 1, 100);
|
|
if ((mp_int_t)ticks < 0) {
|
|
goto timeout;
|
|
}
|
|
buf[i / 8] = (buf[i / 8] << 1) | (ticks > 48);
|
|
}
|
|
|
|
mp_hal_quiet_timing_exit(irq_state);
|
|
return mp_const_none;
|
|
|
|
timeout:
|
|
mp_hal_quiet_timing_exit(irq_state);
|
|
mp_raise_OSError(MP_ETIMEDOUT);
|
|
}
|
|
MP_DEFINE_CONST_FUN_OBJ_2(dht_readinto_obj, dht_readinto);
|