45 lines
1.4 KiB
C
45 lines
1.4 KiB
C
// SPDX-FileCopyrightText: 2014 MicroPython & CircuitPython contributors (https://github.com/adafruit/circuitpython/graphs/contributors)
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// SPDX-FileCopyrightText: Copyright (c) 2016 Damien P. George
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//
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// SPDX-License-Identifier: MIT
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#include "py/runtime.h"
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#include "py/mperrno.h"
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#include "extmod/machine_pulse.h"
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#if MICROPY_PY_MACHINE_PULSE
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mp_uint_t machine_time_pulse_us(mp_hal_pin_obj_t pin, int pulse_level, mp_uint_t timeout_us) {
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mp_uint_t start = mp_hal_ticks_us();
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while (mp_hal_pin_read(pin) != pulse_level) {
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if ((mp_uint_t)(mp_hal_ticks_us() - start) >= timeout_us) {
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return (mp_uint_t)-2;
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}
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}
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start = mp_hal_ticks_us();
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while (mp_hal_pin_read(pin) == pulse_level) {
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if ((mp_uint_t)(mp_hal_ticks_us() - start) >= timeout_us) {
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return (mp_uint_t)-1;
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}
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}
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return mp_hal_ticks_us() - start;
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}
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STATIC mp_obj_t machine_time_pulse_us_(size_t n_args, const mp_obj_t *args) {
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mp_hal_pin_obj_t pin = mp_hal_get_pin_obj(args[0]);
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int level = 0;
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if (mp_obj_is_true(args[1])) {
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level = 1;
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}
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mp_uint_t timeout_us = 1000000;
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if (n_args > 2) {
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timeout_us = mp_obj_get_int(args[2]);
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}
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mp_uint_t us = machine_time_pulse_us(pin, level, timeout_us);
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// May return -1 or -2 in case of timeout
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return mp_obj_new_int(us);
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}
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MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_time_pulse_us_obj, 2, 3, machine_time_pulse_us_);
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#endif
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