stm32f407-openocd/Core/Src/temp_sensor/ds18b20.c

/**
 * @ Author: Yifan Chen
 * @ Create Time: 2024-06-13 09:04:07
 * @ Modified by: Yifan Chen
 * @ Modified time: 2024-06-13 15:03:03
 * @ Description:
 */

#include "ds18b20.h"
#include <stdio.h>
extern void ds18b20_io_out(unsigned char ch);
extern void ds18b20_write(unsigned char ch, unsigned char value);
extern unsigned char ds18b20_read(unsigned char ch);

__attribute__((weak)) void delay_us(unsigned int us)
{
    for (volatile int i = 0; i < us; i++)
    {
        for (volatile int j = 0; j < 13; j++)
        {
            ;
        }
    }
}
/*
    向DS18B20写入数据
*/
void ds18b20_write_data(unsigned char ch, unsigned char byte)
{

    unsigned char tempIndex, tempData;
    // ds18b20_io_out(ch);
    for (tempIndex = 1; tempIndex <= 8; tempIndex++)
    {
        tempData = (byte & 0x01);
        byte >>= 1;
        if (tempData == 1)
        {
            ds18b20_write(ch, 0); // 低电平
            delay_us(2);
            ds18b20_write(ch, 1); // 高电平
            delay_us(60);         // 延时60us
        }
        else
        {
            ds18b20_write(ch, 0); // 低电平
            delay_us(60);         // 延时60us
            ds18b20_write(ch, 1); // 高电平
            delay_us(2);
        }
    }
}
/*
    读取DS18B20一位数据
*/
unsigned char ds18b20_read_bit(unsigned char ch)
{
    unsigned char data = 0;
    ds18b20_write(ch, 0); // 低电平
    delay_us(2);
    ds18b20_write(ch, 1); // 高电平
    delay_us(15);
    data = ds18b20_read(ch);
    // ds18b20_io_out(ch);   // 设置为输出
    ds18b20_write(ch, 1); // 高电平
    delay_us(45);
    return data;
}
/*
    读取DS18B20的数据
*/
unsigned char ds18b20_read_data(unsigned char ch)
{
    unsigned char i, j, data = 0;

    for (i = 1; i <= 8; i++)
    {
        j = ds18b20_read_bit(ch);
        data = (j << 7) | (data >> 1);
    }
    return data;
}

/**
 * return 0 : rst success return 1 : rst failure
 */
char ds18b20_rst(unsigned char io)
{
    // ds18b20_io_out(io);
    ds18b20_write(io, 0);
    delay_us(480);
    ds18b20_write(io, 1);
    delay_us(120);
    unsigned char val = ds18b20_read(io);
    // ds18b20_io_out(io);
    ds18b20_write(io, 1);
    delay_us(360);
    return val;
}

float ds18b20_read_temp(unsigned char ch)
{
    unsigned short temp = 0;
    ds18b20_rst(ch);
    ds18b20_write_data(ch, 0xcc);
    ds18b20_write_data(ch, 0xbe);
    delay_us(1000);
    temp = ds18b20_read_data(ch);
    temp |= (ds18b20_read_data(ch) << 8);
    float temp_f = 0.0625 * (float)temp;
    return temp_f;
}
void ds18b20_start_convert(unsigned char ch)
{
    ds18b20_rst(ch);
    ds18b20_write_data(ch, 0xcc);
    ds18b20_write_data(ch, 0x44);
}
void ds18b20_io_init(unsigned char ch)
{
    ds18b20_io_out(ch);
    ds18b20_write(ch, 1);
}