esp8266-clock/main/tm1637.c

/*
 * SPDX-FileCopyrightText: 2022 Helmut Pozimski <helmut@pozimski.eu>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 */
 
 #include <stdint.h>
 #include <driver/gpio.h>
 
 #include "tm1637.h"
 
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 
 #define DATA_COMMAND 0x40
 #define DISPLAY_COMMAND 0x88
 #define ADDRESS_COMMAND 0xC0
 
 // INPUT = 1, OUTPUT = 0
 // INPUT = 1, OUTPUT = 0
 
 static void delay() {
 	vTaskDelay(1 / portTICK_PERIOD_MS);
 }
 
 esp_err_t tm1637_init(tm1637_config* config, uint8_t clk_pin, uint8_t dio_pin, bool show_colon, uint8_t brightness) {
 	gpio_config_t io_conf;
 	esp_err_t ret;
 	io_conf.intr_type = GPIO_INTR_DISABLE;
 	io_conf.mode = GPIO_MODE_OUTPUT;
 	io_conf.pin_bit_mask = ((1ULL<<clk_pin)) | ((1ULL<<dio_pin));
 	io_conf.pull_down_en = 0;
 	io_conf.pull_up_en = 0;
 	ret = gpio_config(&io_conf);
	config->clk_pin = clk_pin;
	config->dio_pin = dio_pin;
	config->show_colon = show_colon;
	config->brightness = brightness;
	gpio_set_level(dio_pin, 1);
	gpio_set_level(clk_pin, 1);
	delay();
	return ret;
 }
 
static void start_transfer(tm1637_config* config) {
	gpio_set_level(config->dio_pin, 0);
	delay(); 
}

static void stop_transfer(tm1637_config* config) {
	gpio_set_level(config->dio_pin, 0);
	delay();
	gpio_set_level(config->clk_pin, 1);
	delay();
	gpio_set_level(config->dio_pin, 1);
	delay(); 
}
 
 static void write_byte(tm1637_config* config, uint8_t byte) {
 	uint8_t data = byte;
	
	for (uint8_t i = 0; i<8; i++) {
		gpio_set_level(config->clk_pin, 0);
		delay();
		gpio_set_level(config->dio_pin, data & 0x01);
		delay();
		gpio_set_level(config->clk_pin, 1);
		delay();
		data = data >> 1;
	}
	
	gpio_set_level(config->clk_pin, 0);
	delay();
	gpio_set_level(config->dio_pin, 1);	
	delay();
	gpio_set_level(config->clk_pin, 1);
	
	delay();
	
	gpio_set_direction(config->dio_pin, GPIO_MODE_INPUT);
	
	delay();
	
	int result = -1;
	
	while (result != 0) {
		result = gpio_get_level(config->dio_pin);
	}
	
	delay();
	gpio_set_level(config->clk_pin, 0);
	delay();
	gpio_set_direction(config->dio_pin, GPIO_MODE_OUTPUT);
	delay();
 }
 
esp_err_t tm1637_set_segment(tm1637_config* config, uint8_t value, uint8_t segment) {
	uint16_t write_value = NUMERALS[value];
	if (config->show_colon) {
		write_value |= 0x80;
	}
	start_transfer(config);
	write_byte(config, DATA_COMMAND);
	stop_transfer(config);
	
	start_transfer(config);
	write_byte(config, ADDRESS_COMMAND | segment);
	
	write_byte(config, write_value);
	stop_transfer(config);
	
	start_transfer(config);
	write_byte(config, DISPLAY_COMMAND | (config->brightness & 0x07));
	stop_transfer(config);
	return 0;
}