#define _DS18B20_LOCAL
#include "ds18b20.h"
#include "stm32f10x.h"
#include "stm32f10x_conf.h"
//把下面这段复制到主程序
/**************************************************************************/
// TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
// RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
// TIM_TimeBaseStructure.TIM_Period = 1; //自动装载
// TIM_TimeBaseStructure.TIM_Prescaler = 72; //72M分频率到1MHz
// TIM_TimeBaseStructure.TIM_ClockDivision = 0;
// TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Down; //向下计数
// TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
/**************************************************************************/
void delay_nus(vu32 nCount)
{
u16 TIMCounter = nCount;
TIM_Cmd(TIM2, ENABLE);
TIM_SetCounter(TIM2, TIMCounter);
while (TIMCounter)
{
TIMCounter = TIM_GetCounter(TIM2);
}
TIM_Cmd(TIM2, DISABLE);
}
/*******************************************************************************
*******************************************************************************/
void DS18B20_init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
// PC9-DQ
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(DS18B20_PORT, &GPIO_InitStructure);
}
//单总线上的所有处理均从初始化开始
void init_1820()
{
DIR_1WIRE_OUT();
SET_OP_1WIRE();
CLR_OP_1WIRE();
delay_nus(500); //480us以上
SET_OP_1WIRE();
DIR_1WIRE_IN();
delay_nus(30); //15~60us
while(CHECK_IP_1WIRE());
DIR_1WIRE_OUT();
SET_OP_1WIRE();
delay_nus(100); //60~240us
}
/*
指令 代码
Read ROM(读ROM) [33H]
Match ROM(匹配ROM) [55H]
Skip ROM(跳过ROM] [CCH]
Search ROM(搜索ROM) [F0H]
Alarm search(告警搜索) [ECH]
指令 代码
Write Scratchpad(写暂存存储器) [4EH]
Read Scratchpad(读暂存存储器) [BEH]
Copy Scratchpad(复制暂存存储器) [48H]
Convert Temperature(温度变换) [44H]
Recall EPROM(重新调出) [B8H]
Read Power supply(读电源) [B4H]
*/
void write_1820(u8 x)
{
u16 i;
for(i=0; i<8; i++)
{
CLR_OP_1WIRE();
if(x & 0x01) //写数据了，先写低位的！
SET_OP_1WIRE();
else
CLR_OP_1WIRE();
x>>=1;
delay_nus(30); //15~60us
SET_OP_1WIRE();
}
SET_OP_1WIRE();
}
u8 read_1820(void)
{
u16 i;
u8 x = 0;
DIR_1WIRE_OUT();
for(i=0; i<8; i++)
{
CLR_OP_1WIRE();
x >>= 1;
SET_OP_1WIRE();
DIR_1WIRE_IN();
//读数据,从低位开始
if(CHECK_IP_1WIRE())
x |= 0x80;
delay_nus(100); //60~120us
DIR_1WIRE_OUT();
}
return (x);
}
/*
返回值是温度
格式s,s,s,s, s,b6,b5,b4, b3,b2,b1,b0, b-1,b-2,b-3,b-4
转换为十进制
温度 T = (int)val*10/16;
放大了10倍，个位是小数部分。
*/
void DS18B20_Convert(void) //温度转换
{
init_1820(); //复位18b20
write_1820(0xcc); // 发出转换命令
write_1820(0x44);
}
u16 DS18B20_Read(void) //读取温度值
{
u16 res;
init_1820();
write_1820(0xcc); //发出读命令
write_1820(0xbe);
res=read_1820(); //读数据
res+=(u16)read_1820()<<8;
return res;
}
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