circuitpython/shared-module/keypad/ShiftRegisterKeys.c

135 lines
5.4 KiB
C

/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2021 Dan Halbert 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 <string.h>
#include "py/gc.h"
#include "py/runtime.h"
#include "shared-bindings/digitalio/DigitalInOut.h"
#include "shared-bindings/keypad/EventQueue.h"
#include "shared-bindings/keypad/ShiftRegisterKeys.h"
#include "shared-bindings/keypad/__init__.h"
#include "shared-bindings/supervisor/__init__.h"
#include "supervisor/port.h"
#include "supervisor/shared/tick.h"
static void shiftregisterkeys_scan_now(void *self, mp_obj_t timestamp);
static size_t shiftregisterkeys_get_key_count(void *self);
static keypad_scanner_funcs_t shiftregisterkeys_funcs = {
.scan_now = shiftregisterkeys_scan_now,
.get_key_count = shiftregisterkeys_get_key_count,
};
void common_hal_keypad_shiftregisterkeys_construct(keypad_shiftregisterkeys_obj_t *self, const mcu_pin_obj_t *clock_pin, const mcu_pin_obj_t *data_pin, const mcu_pin_obj_t *latch_pin, bool value_to_latch, size_t key_count, bool value_when_pressed, mp_float_t interval, size_t max_events) {
digitalio_digitalinout_obj_t *clock = m_new_obj(digitalio_digitalinout_obj_t);
clock->base.type = &digitalio_digitalinout_type;
common_hal_digitalio_digitalinout_construct(clock, clock_pin);
common_hal_digitalio_digitalinout_switch_to_output(clock, false, DRIVE_MODE_PUSH_PULL);
self->clock = clock;
digitalio_digitalinout_obj_t *data = m_new_obj(digitalio_digitalinout_obj_t);
data->base.type = &digitalio_digitalinout_type;
common_hal_digitalio_digitalinout_construct(data, data_pin);
common_hal_digitalio_digitalinout_switch_to_input(data, PULL_NONE);
self->data = data;
digitalio_digitalinout_obj_t *latch = m_new_obj(digitalio_digitalinout_obj_t);
latch->base.type = &digitalio_digitalinout_type;
common_hal_digitalio_digitalinout_construct(latch, latch_pin);
common_hal_digitalio_digitalinout_switch_to_output(latch, true, DRIVE_MODE_PUSH_PULL);
self->latch = latch;
self->value_to_latch = value_to_latch;
self->value_when_pressed = value_when_pressed;
self->key_count = key_count;
self->funcs = &shiftregisterkeys_funcs;
keypad_construct_common((keypad_scanner_obj_t *)self, interval, max_events);
}
void common_hal_keypad_shiftregisterkeys_deinit(keypad_shiftregisterkeys_obj_t *self) {
if (common_hal_keypad_deinited(self)) {
return;
}
// Remove self from the list of active keypad scanners first.
keypad_deregister_scanner((keypad_scanner_obj_t *)self);
common_hal_digitalio_digitalinout_deinit(self->clock);
self->clock = MP_ROM_NONE;
common_hal_digitalio_digitalinout_deinit(self->data);
self->data = MP_ROM_NONE;
common_hal_digitalio_digitalinout_deinit(self->latch);
self->latch = MP_ROM_NONE;
common_hal_keypad_deinit_core(self);
}
size_t shiftregisterkeys_get_key_count(void *self_in) {
keypad_shiftregisterkeys_obj_t *self = self_in;
return self->key_count;
}
static void shiftregisterkeys_scan_now(void *self_in, mp_obj_t timestamp) {
keypad_shiftregisterkeys_obj_t *self = self_in;
// Latch (freeze) the current state of the input pins.
common_hal_digitalio_digitalinout_set_value(self->latch, self->value_to_latch);
const size_t key_count = shiftregisterkeys_get_key_count(self);
for (mp_uint_t key_number = 0; key_number < key_count; key_number++) {
// Zero-th data appears on on the data pin immediately, without shifting.
common_hal_digitalio_digitalinout_set_value(self->clock, false);
// Remember the previous up/down state.
const bool previous = self->currently_pressed[key_number];
self->previously_pressed[key_number] = previous;
// Get the current state.
const bool current =
common_hal_digitalio_digitalinout_get_value(self->data) == self->value_when_pressed;
self->currently_pressed[key_number] = current;
// Trigger a shift to get the next bit.
common_hal_digitalio_digitalinout_set_value(self->clock, true);
// Record any transitions.
if (previous != current) {
keypad_eventqueue_record(self->events, key_number, current, timestamp);
}
}
// Start reading the input pins again.
common_hal_digitalio_digitalinout_set_value(self->latch, !self->value_to_latch);
}