demo of driving MAX2719 dot matrix displays with STM32F103 Bluepill
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f103-dotmatrix/project/utils/debounce.c

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3.5 KiB

#include "main.h"
#include "debounce.h"
#include "timebase.h"
#include "malloc_safe.h"
// ms debounce time
#define DEF_DEBO_TIME 20
typedef struct {
GPIO_TypeDef *GPIOx; ///< GPIO base
uint16_t pin; ///< bit mask
bool state; ///< current state
bool invert; ///< invert pin
debo_id_t id; ///< pin ID
ms_time_t debo_time; ///< debouncing time (ms)
ms_time_t counter_0; ///< counter for falling edge (ms)
ms_time_t counter_1; ///< counter for rising edge (ms)
void (*falling_cb)(void);
void (*rising_cb)(void);
} debo_slot_t;
/** Number of allocated slots */
static size_t debo_slot_count = 0;
/** Slots array */
static debo_slot_t *debo_slots;
/** Next free pin ID for make_id() */
static debo_id_t next_pin_id = 1;
/**
* @brief Get a valid free pin ID for a new entry.
* @return the ID.
*/
static debo_id_t make_id(void)
{
debo_id_t id = next_pin_id++;
// make sure no task is given PID 0
if (next_pin_id == DEBO_PIN_NONE) {
next_pin_id++;
}
return id;
}
/** Init the debouncer */
void debounce_init(size_t slot_count)
{
debo_slots = calloc_s(slot_count, sizeof(debo_slot_t));
debo_slot_count = slot_count;
}
/** Register a pin */
debo_id_t debo_register_pin(debo_init_t *init)
{
assert_param(IS_GPIO_ALL_PERIPH(init->GPIOx));
assert_param(IS_GET_GPIO_PIN(init->pin));
for (size_t i = 0; i < debo_slot_count; i++) {
debo_slot_t *slot = &debo_slots[i];
if (slot->id != DEBO_PIN_NONE) continue; // slot is used
slot->GPIOx = init->GPIOx;
slot->pin = init->pin;
slot->falling_cb = init->falling_cb;
slot->rising_cb = init->rising_cb;
slot->invert = init->invert;
slot->counter_0 = 0;
slot->counter_1 = 0;
slot->debo_time = (init->debo_time == 0) ? DEF_DEBO_TIME : init->debo_time;
bool state = GPIO_ReadInputDataBit(slot->GPIOx, slot->pin);
if (slot->invert) state = !state;
slot->state = state;
slot->id = make_id();
return slot->id;
}
return DEBO_PIN_NONE;
}
/** Callback that must be called every 1 ms */
void debo_periodic_task(void)
{
for (size_t i = 0; i < debo_slot_count; i++) {
debo_slot_t *slot = &debo_slots[i];
if (slot->id == DEBO_PIN_NONE) continue; // unused
bool state = GPIO_ReadInputDataBit(slot->GPIOx, slot->pin);
if (slot->invert) state = !state;
if (slot->state != state) {
if (state == 0) {
// falling
if (slot->counter_0++ == slot->debo_time) {
slot->state = 0;
if (slot->falling_cb != NULL) {
slot->falling_cb();
}
}
} else {
// rising
if (slot->counter_1++ == slot->debo_time) {
slot->state = 1;
if (slot->rising_cb != NULL) {
slot->rising_cb();
}
}
}
} else {
// reset counters
slot->counter_0 = 0;
slot->counter_1 = 0;
}
}
}
/**
* @brief Check if a pin is high
* @param pin_id : Slot ID
* @return true if the pin is registered and is HIGH
*/
bool debo_pin_state(debo_id_t pin_id)
{
if (pin_id == DEBO_PIN_NONE) return false;
for (size_t i = 0; i < debo_slot_count; i++) {
debo_slot_t *slot = &debo_slots[i];
if (slot->id != pin_id) continue;
return slot->state;
}
return false;
}
/**
* @brief Remove a pin entry from the debouncer.
* @param pin_id : Slot ID
* @return true if task found & removed.
*/
bool debo_remove_pin(debo_id_t pin_id)
{
if (pin_id == DEBO_PIN_NONE) return false;
for (size_t i = 0; i < debo_slot_count; i++) {
debo_slot_t *slot = &debo_slots[i];
if (slot->id != pin_id) continue;
slot->id = DEBO_PIN_NONE;
return true;
}
return false;
}