STM8单片机读取18B20温度传感器

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#include "ds18b20.h"
#include "stm8s103f.h"
#include "delay.h"

#define DS18B20_DQ_OUT          PA_DDR |= 0x08   //输出
#define DS18B20_DQ_IN           PA_DDR &= 0xf7   //输入
#define DS18B20_DQ_HIGH         PA_ODR |= 0x08   //拉高
#define DS18B20_DQ_LOW          PA_ODR &= 0xf7   //拉低
#define DS18B20_DQ_PULL_UP      PA_CR1 |= 0x08   //上拉输入
#define DS18B20_DQ_FLOATING     PA_CR1 &= 0xf7    //浮空输入
#define DS18B20_DQ_PUSH_PULL    PA_CR1 |= 0x08   //推挽输出
#define DS18B20_DQ_OPEN_DRAIN   PA_CR1 &= 0xf7    //开漏输出
#define DS18B20_DQ_VALUE        PA_IDR &0x08       //DQ值

void DS18B20_Init( void )
{
	DS18B20_DQ_OUT;
	DS18B20_DQ_PUSH_PULL;
	DS18B20_DQ_HIGH;
	delay_us( 10 );
	DS18B20_DQ_LOW;
	delay_us( 600 ); /*复位脉冲 */

	DS18B20_DQ_IN;
	DS18B20_DQ_PULL_UP;
	delay_us( 60 );
	while ( DS18B20_DQ_VALUE == 1 )
		;
	delay_us( 400 );
}
void DS18B20_WriteByte(unsigned char _data)
{
	unsigned char i = 0;
	DS18B20_DQ_OUT;
	for ( i = 0; i < 8; i++ )
	{
		DS18B20_DQ_LOW;
		delay_us( 2 );
		if ( _data & 0x01 )
		{
			DS18B20_DQ_HIGH;
		}
		_data >>= 1;
		delay_us( 60 );
		DS18B20_DQ_HIGH;
	}
}
unsigned char DS18B20_ReadByte(void)
{
	unsigned char i = 0, _data = 0;
	for ( i = 0; i < 8; i++ )
	{
		DS18B20_DQ_OUT;
		DS18B20_DQ_LOW;
		delay_us( 5 );
		_data >>= 1;
		DS18B20_DQ_HIGH;
		DS18B20_DQ_IN;
		if ( DS18B20_DQ_VALUE )
		{
			_data |= 0x80;
		}
		DS18B20_DQ_OUT;
		DS18B20_DQ_HIGH;
		delay_us( 60 );
	}

	return(_data);
}

float DS18B20_ReadTemperature(void)
{
	unsigned char  temp = 0;
	float t= 0;
	DS18B20_Init();
	DS18B20_WriteByte( 0xcc );
	DS18B20_WriteByte( 0x44 );

	DS18B20_Init();
	DS18B20_WriteByte( 0xcc );
	DS18B20_WriteByte( 0xbe );

	temp = DS18B20_ReadByte();
	t = ( ( (temp & 0xf0) >> 4) + (temp & 0x07) * 0.125);
	temp = DS18B20_ReadByte();
	t += ( (temp & 0x0f) << 4);

	return(t);
}

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#include "stm8s103f.h"
#include "ds18b20.h"
#include "delay.h"
/*系统时钟初始化*/
void SysClkInit(void)
{                           //默认值为16M 8分频
	CLK_SWR=0xe1;      //HSI为主时钟源  16MHz CPU时钟频率
	CLK_CKDIVR=0x00;   //CPU时钟0分频，系统时钟0分频 16M 
}
main()
{
    float tem;
    SysClkInit();
    delay_init(16);
    tem=DS18B20_ReadTemperature();
	while (1);
}