ESP32 PCF8574 keypad Driver

ESP-IDF component for 4x3 keypad using a pcf8574 io expander. Meant for the ElectroPower Smart House project. This component has buffer management features such as buffer timeout.

Disclaimer

This was made for educational purposes only and should not be used for production

Example use

#include <driver/i2c.h>
#include <freertos/task.h>
#include <ep_keypad.h>
#include <esp_log.h>
/*
*   I2C address may differ, so consult your pcf module's datasheet
*/
#define KEYPAD_ADDRESS 0x20

keypad_buffer_t	buffer;

void keypad_handler(void* params);
esp_err_t i2c_master_init(void);

void app_main(void)
{
    ESP_ERR_CHECK(i2c_master_init());
    xTaskCreatePinnedToCore(keypad_handler,"keypad handler",4098,NULL,2,NULL,0);
}


void keypad_handler(void* params)
{
	char c = '\0';
	uint8_t clear_pullup = 0xff;
	double prev_time=0;
	double curr_time=0;
	i2c_master_write_to_device(I2C_NUM_0,KEYPAD_ADDRESS, &clear_pullup,1,100);
	init_timer(&buffer);

	while(1)
    {

		timer_get_counter_time_sec(TIMER_GROUP_0,TIMER_0,&curr_time);

		c = poll_keypad(KEYPAD_ADDRESS);

		if((prev_time - curr_time)  > 10) clear_buffer(&buffer);


		switch(c)
		{
			case '*':
				buffer.occupied -= 1;
				(buffer.elements)[buffer.occupied] = '\0';
				prev_time = curr_time;
				break;
			case '#':
				printf("[Buffer]> %s \n",buffer.elements);
				clear_buffer(&buffer);
				prev_time = curr_time;
				break;
			case '\0':
				break;
			default:
				prev_time = curr_time;
                putchar(c);
                putchar('\n');
				add_to_buffer(&buffer,c);
				break;

		}

    	vTaskDelay(50/portTICK_PERIOD_MS);
    }
}

esp_err_t i2c_master_init(void){

    i2c_config_t conf = {
        .mode = I2C_MODE_MASTER,
        .sda_io_num = GPIO_NUM_21,
        .scl_io_num = GPIO_NUM_22,
        .sda_pullup_en = GPIO_PULLUP_ENABLE,
        .scl_pullup_en = GPIO_PULLUP_ENABLE,
        .master.clk_speed = 100000,
    };

    i2c_param_config(I2C_NUM_0, &conf);

    return i2c_driver_install(I2C_NUM_0, conf.mode, 0, 0, 0);
}

Author

Github: abdellah2288

License

GPL v2