circuitpython/shared-module/keypad/ShiftRegisterKeys.c

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/*
* 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"
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#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, mp_uint_t num_data_pins, const mcu_pin_obj_t *data_pins[], const mcu_pin_obj_t *latch_pin, bool value_to_latch, mp_uint_t num_key_counts, size_t key_counts[], bool value_when_pressed, mp_float_t interval, size_t max_events) {
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digitalio_digitalinout_obj_t *clock =
mp_obj_malloc(digitalio_digitalinout_obj_t, &digitalio_digitalinout_type);
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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 *latch = m_new_obj(digitalio_digitalinout_obj_t);
latch->base.type = &digitalio_digitalinout_type;
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common_hal_digitalio_digitalinout_construct(latch, latch_pin);
common_hal_digitalio_digitalinout_switch_to_output(latch, true, DRIVE_MODE_PUSH_PULL);
self->latch = latch;
mp_obj_t dios[num_data_pins];
for (size_t i = 0; i < num_data_pins; i++) {
digitalio_digitalinout_obj_t *dio = m_new_obj(digitalio_digitalinout_obj_t);
dio->base.type = &digitalio_digitalinout_type;
common_hal_digitalio_digitalinout_construct(dio, data_pins[i]);
common_hal_digitalio_digitalinout_switch_to_input(dio, PULL_NONE);
dios[i] = dio;
}
// Allocate a tuple object with the data pins
self->data_pins = mp_obj_new_tuple(num_data_pins, dios);
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self->key_counts = (mp_uint_t *)m_malloc(sizeof(mp_uint_t) * num_key_counts);
self->num_key_counts = num_key_counts;
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// copy to an m_malloc() and on the fly record pin with largest Shift register
mp_uint_t max = 0;
for (mp_uint_t i = 0; i < self->num_key_counts; i++) {
mp_uint_t cnt = key_counts[i];
if (cnt > max) {
max = cnt;
}
self->key_counts[i] = cnt;
}
self->max_key_count = max;
self->value_to_latch = value_to_latch;
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self->value_when_pressed = value_when_pressed;
self->funcs = &shiftregisterkeys_funcs;
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keypad_construct_common((keypad_scanner_obj_t *)self, interval, max_events);
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}
void common_hal_keypad_shiftregisterkeys_deinit(keypad_shiftregisterkeys_obj_t *self) {
if (common_hal_keypad_deinited(self)) {
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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->latch);
self->latch = MP_ROM_NONE;
for (size_t key = 0; key < self->data_pins->len; key++) {
common_hal_digitalio_digitalinout_deinit(self->data_pins->items[key]);
}
self->data_pins = MP_ROM_NONE;
self->key_counts = MP_ROM_NONE;
common_hal_keypad_deinit_core(self);
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}
size_t shiftregisterkeys_get_key_count(void *self_in) {
keypad_shiftregisterkeys_obj_t *self = self_in;
size_t total = 0;
for (mp_uint_t i = 0; i < self->num_key_counts; i++) {
total += self->key_counts[i];
}
return total;
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}
static void shiftregisterkeys_scan_now(void *self_in, mp_obj_t timestamp) {
keypad_shiftregisterkeys_obj_t *self = self_in;
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// Latch (freeze) the current state of the input pins.
common_hal_digitalio_digitalinout_set_value(self->latch, self->value_to_latch);
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// Scan for max_key_count bit
for (mp_uint_t scan_number = 0; scan_number < self->max_key_count; scan_number++) {
common_hal_digitalio_digitalinout_set_value(self->clock, false);
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// Zero-th data appears on on the data pin immediately, without shifting.
// Loop through all the data pins that share the latch
mp_uint_t index = 0;
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for (mp_uint_t i = 0; i < self->data_pins->len; i++) {
// When this data pin has less shiftable bits, ignore it
if (scan_number >= self->key_counts[i]) {
continue;
}
mp_uint_t key_number = scan_number + index;
// 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_pins->items[i]) == self->value_when_pressed;
self->currently_pressed[key_number] = current;
// Record any transitions.
if (previous != current) {
keypad_eventqueue_record(self->events, key_number, current, timestamp);
}
index += self->key_counts[i];
}
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// Trigger a shift to get the next bit.
common_hal_digitalio_digitalinout_set_value(self->clock, true);
}
// Start reading the input pins again.
common_hal_digitalio_digitalinout_set_value(self->latch, !self->value_to_latch);
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}