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ds18b20.c
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ds18b20.c
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/* github.com/jinzhifeng */
/* QQ : 356290462 */
/* jin-zhifeng@hotmail.com */
#include "ds18b20.h"
DS18B20_CheckState DS18B20_Init(void)
/**
* \brief Init Ds18b20 初始化
*
* \param None
*
* \retval AckFlag
*/
{
DS18B20_CheckState AckFlag;
DS18B20_DQ_SET(); //释放总线为高电平初始态
DS18B20_DelayXus(100);
DS18B20_DQ_CLR(); //拉低总线
DS18B20_DelayXus(500); //精确延时,维持至少480us
DS18B20_DQ_SET(); //释放总线
DS18B20_DelayXus(50); //等待15-60us后,检测ds18b20是否发出的60-240us低电平存在脉冲
if(ReadPin_DS18B20_DQ() == GPIO_PIN_RESET) //读DS18B20是否发出低电平存在脉冲
{
AckFlag = DS18B20_Exist;
// printf("检测到DS18B20温度传感器...\r\n");
}
else
{
AckFlag = DS18B20_NotExist;
printf("未检测到DS18B20温度传感器...请检查线路!\r\n");
}
DS18B20_DelayXus(100);
return AckFlag;
}
uint8_t DS18B20_ReadOneByte(void)
/**
* \brief 主机向Ds18b20读1个字节的数据
*
* \param None
*
* \retval RdData
*/
{
uint8_t i, ReadData = 0; //必须将默认值设为0，否则需要加ReadData &= 0x7F;
for(i = 0; i < 8; i++)
{
DS18B20_DQ_CLR(); //拉低总线
DS18B20_DelayXus(1);
DS18B20_DQ_SET(); //释放总线
ReadData >>= 1; //准备下一位
if(ReadPin_DS18B20_DQ())
ReadData |= 0x80;
else
ReadData &= 0x7F;
DS18B20_DelayXus(65);
DS18B20_DQ_SET(); //释放总线
}
return ReadData;
}
void DS18B20_WriteOneByte(uint8_t WriteByte)
/**
* \brief 主机向Ds18b20写1个字节的数据
*
* \param WriteByte
*
* \retval None
*/
{
uint8_t i;
for(i = 0; i < 8; i++)
{
DS18B20_DQ_CLR(); //拉低总线
if(WriteByte & 0x01)
DS18B20_DQ_SET(); //释放总线
else
DS18B20_DQ_CLR(); //拉低总线
DS18B20_DelayXus(65);
DS18B20_DQ_SET(); //释放总线
WriteByte >>= 1; //准备下一位
}
}
float Get_DS18B20_Temperature(void)
/**
* \brief 主机向Ds18b20读温度值
*
* \param None
*
* \retval Temperature
*/
{
uint8_t TL;
uint16_t TH;
float Temperature;
DS18B20_Init();
DS18B20_WriteOneByte(SKIP_ROM); //跳过读序列号的操作
DS18B20_WriteOneByte(CONVERT_T); //启动温度转换
DS18B20_DelayXus(20);
DS18B20_Init();
DS18B20_WriteOneByte(SKIP_ROM); //跳过读序列号的操作
DS18B20_WriteOneByte(READ_SCRATCHPAD); //读温度寄存器,共9个byte,前两个byte为温度值
TL = DS18B20_ReadOneByte(); //TL存低字节
TH = DS18B20_ReadOneByte(); //TH存高字节
// TH <<= 4;
// TH += (TL & 0xF0) >> 4;
// Temperature = TH;
TH <<= 8;
TH |= TL;
Temperature = TH * 0.0625;
return Temperature;
}
volatile void DS18B20_DelayXus(uint32_t DelayXus)
/**
* \brief 延时子程序,延时DelayXus微秒
*
* \param DelayXus
*
* \retval None
*/
{
uint32_t dwCurCounter = 0;
uint32_t dwPreTickVal = SysTick->VAL;
uint32_t dwCurTickVal;
DelayXus = DelayXus * (HAL_RCC_GetHCLKFreq() / 1000000);
for(;;)
{
dwCurTickVal = SysTick -> VAL;
if(dwCurTickVal < dwPreTickVal)
{
dwCurCounter = dwCurCounter + dwPreTickVal - dwCurTickVal;
}
else
{
dwCurCounter = dwCurCounter + dwPreTickVal + SysTick->LOAD - dwCurTickVal;
}
dwPreTickVal = dwCurTickVal;
if(dwCurCounter >= DelayXus)
{
return;
}
}
}
/* github.com/jinzhifeng */
/* QQ : 356290462 */
/* jin-zhifeng@hotmail.com */