circuitpython/shared-bindings/pulseio/PulseIn.c

/*
 * This file is part of the Micro Python project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2017 Scott Shawcroft for Adafruit Industries
 *
 * 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 "lib/utils/context_manager_helpers.h"
#include "py/objproperty.h"
#include "py/runtime.h"
#include "py/runtime0.h"
#include "shared-bindings/microcontroller/Pin.h"
#include "shared-bindings/pulseio/PulseIn.h"

//| .. currentmodule:: pulseio
//|
//| :class:`PulseIn` -- Read a series of pulse durations
//| ========================================================
//|
//| PulseIn is used to measure a series of active and idle pulses. This is
//| commonly used in infrared receivers and low cost temperature sensors (DHT).
//| The pulsed signal consists of timed active and idle periods. Unlike PWM,
//| there is no set duration for active and idle pairs.
//|
//| .. class:: PulseIn(pin, maxlen=2, \*, idle_state=False)
//|
//|   Create a PulseIn object associated with the given pin. The object acts as
//|   a read-only sequence of pulse lengths with a given max length. When it is
//|   active, new pulse lengths are added to the end of the list. When there is
//|   no more room (len() == `maxlen`) the oldest pulse length is removed to
//|   make room.
//|
//|   :param ~microcontroller.Pin pin: Pin to read pulses from.
//|   :param int maxlen: Maximum number of pulse durations to store at once
//|   :param bool idle_state: Idle state of the pin. At start and after `resume`
//|     the first recorded pulse will the opposite state from idle.
//|
//|   Read a short series of pulses::
//|
//|     import pulseio
//|     import board
//|
//|     with pulseio.PulseIn(board.D7) as pulses:
//|         # Wait for an active pulse
//|         while len(pulses) == 0:
//|             pass
//|         # Pause while we do something with the pulses
//|         pulses.pause()
//|
//|         # Print the pulses. pulses[0] is an active pulse unless the length
//|         # reached max length and idle pulses are recorded.
//|         print(pulses)
//|
//|         # Clear the rest
//|         pulse_in.clear()
//|
//|         # Resume with an 80 microsecond active pulse
//|         pulse_in.resume(80)
//|
STATIC mp_obj_t pulseio_pulsein_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *pos_args) {
    mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
    mp_map_t kw_args;
    mp_map_init_fixed_table(&kw_args, n_kw, pos_args + n_args);
    enum { ARG_pin, ARG_maxlen, ARG_idle_state };
    static const mp_arg_t allowed_args[] = {
        { MP_QSTR_pin, MP_ARG_REQUIRED | MP_ARG_OBJ },
        { MP_QSTR_maxlen, MP_ARG_INT, {.u_int = 2} },
        { MP_QSTR_idle_state, MP_ARG_BOOL, {.u_bool = false} },
    };
    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
    mp_arg_parse_all(n_args, pos_args, &kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
    assert_pin(args[ARG_pin].u_obj, false);
    const mcu_pin_obj_t* pin = MP_OBJ_TO_PTR(args[ARG_pin].u_obj);
    assert_pin_free(pin);

    pulseio_pulsein_obj_t *self = m_new_obj(pulseio_pulsein_obj_t);
    self->base.type = &pulseio_pulsein_type;

    common_hal_pulseio_pulsein_construct(self, pin, args[ARG_maxlen].u_int,
        args[ARG_idle_state].u_bool);

    return MP_OBJ_FROM_PTR(self);
}

//|   .. method:: deinit()
//|
//|      Deinitialises the PulseIn and releases any hardware resources for reuse.
//|
STATIC mp_obj_t pulseio_pulsein_deinit(mp_obj_t self_in) {
    pulseio_pulsein_obj_t *self = MP_OBJ_TO_PTR(self_in);
    common_hal_pulseio_pulsein_deinit(self);
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(pulseio_pulsein_deinit_obj, pulseio_pulsein_deinit);

//|   .. method:: __enter__()
//|
//|      No-op used by Context Managers.
//|
//  Provided by context manager helper.

//|   .. method:: __exit__()
//|
//|      Automatically deinitializes the hardware when exiting a context.
//|
STATIC mp_obj_t pulseio_pulsein_obj___exit__(size_t n_args, const mp_obj_t *args) {
    (void)n_args;
    common_hal_pulseio_pulsein_deinit(args[0]);
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pulseio_pulsein___exit___obj, 4, 4, pulseio_pulsein_obj___exit__);

//|   .. method:: pause()
//|
//|     Pause pulse capture
//|
STATIC mp_obj_t pulseio_pulsein_obj_pause(mp_obj_t self_in) {
    pulseio_pulsein_obj_t *self = MP_OBJ_TO_PTR(self_in);

    common_hal_pulseio_pulsein_pause(self);
    return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_1(pulseio_pulsein_pause_obj, pulseio_pulsein_obj_pause);

//|   .. method:: resume(trigger_duration=0)
//|
//|     Resumes pulse capture after an optional trigger pulse.
//|
//|     .. warning:: Using trigger pulse with a device that drives both high and
//|       low signals risks a short. Make sure your device is open drain (only
//|       drives low) when using a trigger pulse. You most likely added a
//|       "pull-up" resistor to your circuit to do this.
//|
//|     :param int trigger_duration: trigger pulse duration in microseconds
//|
STATIC mp_obj_t pulseio_pulsein_obj_resume(mp_obj_t self_in, mp_obj_t duration_obj) {
    pulseio_pulsein_obj_t *self = MP_OBJ_TO_PTR(self_in);
    uint16_t trigger_duration = 0;
    if (MP_OBJ_IS_SMALL_INT(duration_obj)) {
        trigger_duration = MP_OBJ_SMALL_INT_VALUE(duration_obj);
    } else if (duration_obj != mp_const_none) {
        mp_raise_TypeError("trigger_duration must be int");
    }

    common_hal_pulseio_pulsein_resume(self, trigger_duration);
    return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_2(pulseio_pulsein_resume_obj, pulseio_pulsein_obj_resume);

//|   .. method:: clear()
//|
//|     Clears all captured pulses
//|
STATIC mp_obj_t pulseio_pulsein_obj_clear(mp_obj_t self_in) {
    pulseio_pulsein_obj_t *self = MP_OBJ_TO_PTR(self_in);

    common_hal_pulseio_pulsein_clear(self);
    return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_1(pulseio_pulsein_clear_obj, pulseio_pulsein_obj_clear);

//|   .. method:: popleft()
//|
//|     Removes and returns the oldest read pulse.
//|
STATIC mp_obj_t pulseio_pulsein_obj_popleft(mp_obj_t self_in) {
    pulseio_pulsein_obj_t *self = MP_OBJ_TO_PTR(self_in);
    return MP_OBJ_NEW_SMALL_INT(common_hal_pulseio_pulsein_popleft(self));
}
MP_DEFINE_CONST_FUN_OBJ_1(pulseio_pulsein_popleft_obj, pulseio_pulsein_obj_popleft);

//|   .. attribute:: maxlen
//|
//|     Returns the maximum length of the PulseIn. When len() is equal to maxlen,
//|     it is unclear which pulses are active and which are idle.
//|
STATIC mp_obj_t pulseio_pulsein_obj_get_maxlen(mp_obj_t self_in) {
    pulseio_pulsein_obj_t *self = MP_OBJ_TO_PTR(self_in);
    return MP_OBJ_NEW_SMALL_INT(common_hal_pulseio_pulsein_get_maxlen(self));
}
MP_DEFINE_CONST_FUN_OBJ_1(pulseio_pulsein_get_maxlen_obj, pulseio_pulsein_obj_get_maxlen);

const mp_obj_property_t pulseio_pulsein_maxlen_obj = {
    .base.type = &mp_type_property,
    .proxy = {(mp_obj_t)&pulseio_pulsein_get_maxlen_obj,
              (mp_obj_t)&mp_const_none_obj,
              (mp_obj_t)&mp_const_none_obj},
};

//|   .. method:: __len__()
//|
//|     Returns the current pulse length
//|
//|     This allows you to::
//|
//|       pulses = pulseio.PulseIn(pin)
//|       print(len(pulses))
//|
STATIC mp_obj_t pulsein_unary_op(mp_uint_t op, mp_obj_t self_in) {
    pulseio_pulsein_obj_t *self = MP_OBJ_TO_PTR(self_in);
    uint16_t len = common_hal_pulseio_pulsein_get_len(self);
    switch (op) {
        case MP_UNARY_OP_BOOL: return mp_obj_new_bool(len != 0);
        case MP_UNARY_OP_LEN: return MP_OBJ_NEW_SMALL_INT(len);
        default: return MP_OBJ_NULL; // op not supported
    }
}

//|   .. method:: __get__(index)
//|
//|     Returns the value at the given index or values in slice.
//|
//|     This allows you to::
//|
//|       pulses = pulseio.PulseIn(pin)
//|       print(pulses[0])
//|
STATIC mp_obj_t pulsein_subscr(mp_obj_t self_in, mp_obj_t index_obj, mp_obj_t value) {
    if (value == mp_const_none) {
        // delete item
        mp_raise_AttributeError("Cannot delete values");
    } else {
        pulseio_pulsein_obj_t *self = MP_OBJ_TO_PTR(self_in);
        if (MP_OBJ_IS_TYPE(index_obj, &mp_type_slice)) {
            mp_raise_NotImplementedError("Slices not supported");
        } else {
            uint16_t index = 0;
            if (MP_OBJ_IS_SMALL_INT(index_obj)) {
                index = MP_OBJ_SMALL_INT_VALUE(index_obj);
            } else {
                mp_raise_TypeError("index must be int");
            }
            if (value == MP_OBJ_SENTINEL) {
                // load
                return MP_OBJ_NEW_SMALL_INT(common_hal_pulseio_pulsein_get_item(self, index));
            } else {
                mp_raise_AttributeError("Read-only");
            }
        }
    }
    return mp_const_none;
}

STATIC const mp_rom_map_elem_t pulseio_pulsein_locals_dict_table[] = {
    // Methods
    { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&pulseio_pulsein_deinit_obj) },
    { MP_ROM_QSTR(MP_QSTR___enter__), MP_ROM_PTR(&default___enter___obj) },
    { MP_ROM_QSTR(MP_QSTR___exit__), MP_ROM_PTR(&pulseio_pulsein___exit___obj) },
    { MP_ROM_QSTR(MP_QSTR_pause), MP_ROM_PTR(&pulseio_pulsein_pause_obj) },
    { MP_ROM_QSTR(MP_QSTR_resume), MP_ROM_PTR(&pulseio_pulsein_resume_obj) },
    { MP_ROM_QSTR(MP_QSTR_clear), MP_ROM_PTR(&pulseio_pulsein_clear_obj) },
    { MP_ROM_QSTR(MP_QSTR_popleft), MP_ROM_PTR(&pulseio_pulsein_popleft_obj) },
    { MP_ROM_QSTR(MP_QSTR_maxlen), MP_ROM_PTR(&pulseio_pulsein_maxlen_obj) },
};
STATIC MP_DEFINE_CONST_DICT(pulseio_pulsein_locals_dict, pulseio_pulsein_locals_dict_table);

const mp_obj_type_t pulseio_pulsein_type = {
    { &mp_type_type },
    .name = MP_QSTR_PulseIn,
    .make_new = pulseio_pulsein_make_new,
    .subscr = pulsein_subscr,
    .unary_op = pulsein_unary_op,
    .locals_dict = (mp_obj_dict_t*)&pulseio_pulsein_locals_dict,
};