#include <stdio.h>
#include "pico/stdlib.h"
#include "hardware/i2c.h"


#define DS1307_ADDR 0x68


uint8_t bcd_to_dec(uint8_t bcd) {
    return ((bcd >> 4) * 10) + (bcd & 0x0F);
}


uint8_t dec_to_bcd(uint8_t decimal) {
    return ((decimal / 10) << 4) | (decimal % 10);
}

// escreve um byte 
void write_byte(uint8_t reg, uint8_t data) {
    uint8_t buf[2];
    buf[0] = reg;
    buf[1] = data;
    i2c_write_blocking(i2c_default, DS1307_ADDR, buf, 2, false);
}

// le um byte 
uint8_t read_byte(uint8_t reg) {
    uint8_t data;
    i2c_write_blocking(i2c_default, DS1307_ADDR, &reg, 1, true);
    i2c_read_blocking(i2c_default, DS1307_ADDR, &data, 1, false);
    return data;
}

// configura a data e hora 
void set_date_time(uint8_t ano, uint8_t mes, uint8_t dia, uint8_t hora, uint8_t minuto, uint8_t segundo) {
    write_byte(0x00, dec_to_bcd(segundo));  
    write_byte(0x01, dec_to_bcd(minuto));  
    write_byte(0x02, dec_to_bcd(hora));    
    write_byte(0x04, dec_to_bcd(dia));     
    write_byte(0x05, dec_to_bcd(mes));   
    write_byte(0x06, dec_to_bcd(ano));    
}

// le a data e hora 
void get_date_time(uint8_t *ano, uint8_t *mes, uint8_t *dia, uint8_t *hora, uint8_t *minuto, uint8_t *segundo) {
    *segundo = bcd_to_dec(read_byte(0x00) & 0x7F);  
    *minuto = bcd_to_dec(read_byte(0x01));        
    *hora = bcd_to_dec(read_byte(0x02) & 0x3F);
    *dia = bcd_to_dec(read_byte(0x04));          
    *mes = bcd_to_dec(read_byte(0x05));       
    *ano = bcd_to_dec(read_byte(0x06));          
}

int main() {
    stdio_init_all();

    
    i2c_init(i2c_default, 100 * 1000);  // 100 kHz
    gpio_set_function(PICO_DEFAULT_I2C_SDA_PIN, GPIO_FUNC_I2C);
    gpio_set_function(PICO_DEFAULT_I2C_SCL_PIN, GPIO_FUNC_I2C);
    gpio_pull_up(PICO_DEFAULT_I2C_SDA_PIN);
    gpio_pull_up(PICO_DEFAULT_I2C_SCL_PIN);

    // data e hora no ds1307
    set_date_time(24, 9, 24, 13, 27, 0);  // 2024/09/24 - 13:27:00

    while (1) {
        uint8_t ano, mes, dia, hora, minuto, segundo;

        // pega a data e hora do ds1307
        get_date_time(&ano, &mes, &dia, &hora, &minuto, &segundo);

        printf("Data: %02d/%02d/20%02d - %02d:%02d:%02d\n", dia, mes, ano, hora, minuto, segundo);

        
        sleep_ms(5000);
    }

    return 0;
}