msp430

MSP430F449与DS18B20驱动程序

#include <msp430x44x.h>

#define SEGE 0X80
#define SEGH 0X40
#define SEGF 0X20
#define SEGC 0X10
#define SEGG 0X08
#define SEGD 0X04
#define SEGB 0X02
#define SEGA 0X01
const unsigned char digit[10] = {
  SEGA|SEGB|SEGC|SEGD|SEGE|SEGF,  /* "0" LCD segments a+b+c+d+e+f */
  0x12,  /* "1" */
  0x8F,  /* "2" */
  0x1F,  /* "3" */
  0x3A,  /* "4" */
  0x3D,  /* "5" */
  0xBD,  /* "6" */
  0x13,  /* "7" */
  0xBF,  /* "8" */
  0x3F   /* "9" */

};


#define DQ1 P4OUT|=BIT4
#define DQ0 P4OUT&=~BIT4

float   Temper=0.0;
int     temperature=0;
unsigned char Error = 0;
//----------------------------------
//功能：us 级别延时
// n=10，则延时10*5+6=56uS
//----------------------------------
void DelayNus(unsigned int n)
{
    while(n--){};
}
//-----------------------------------
//功能：写18B20
//-----------------------------------
void Write_18B20(unsigned char n)
{
    unsigned char i;
    for(i=0;i<8;i++)
    {
        DQ0;
        DelayNus(1);//延时13us 左右
        if((n&0X01)==0X01)  DQ1;
        else DQ0;
        n=n>>1;
        DelayNus(9);//延时50us 以上
        DQ1;
    }
}
//------------------------------------
//功能：读取18B20
//------------------------------------
unsigned char Read_18B20(void)
{
    unsigned char i;
    unsigned char temp;
    for(i=0;i<8;i++)
    {
        temp=temp>>1;
        DQ0;
        _NOP();//延时1us
        DQ1;
        _NOP();_NOP();//延时5us
        _NOP();_NOP();_NOP();
        P4DIR&=~BIT4;
        if((P4IN&BIT4)==0)
        {
            temp=temp&0x7F;
        }else
        {
            temp=temp|0x80;
        }
        DelayNus(7);//延时40us
        P4DIR|=BIT4;
        DQ1;
    }
    return    temp;
}
//-----------------------------------
void Init (void)
{
    DQ0;
    DelayNus(50);//延时500us
    DQ1;
    DelayNus(17);//延时90us
    P4DIR&=~BIT4;
    if((P4IN&BIT4)==BIT4)        //0001 1111b=1f
    {
        Error =1;    //失败1
        P4DIR|=BIT4;
    }else
    {
        Error = 0;//初始化成功
        P4DIR|=BIT4;
        DQ1;
    }
}
//----------------------------------
void Skip(void)
{
    Write_18B20(0xcc);
}
//----------------------------------
void Convert (void)
{
    Write_18B20(0x44);
}

//----------------------------------
void ReadDo (void)
{
    Write_18B20(0xbe);
}
//----------------------------------

void ReadTemp (void)
{
    char temp_low,temp_high; //温度值
    temp_low=Read_18B20(); //读低位
    temp_high=Read_18B20(); //读高位
    temperature=(temp_high&0x0f);
    temperature<<=8;
    temperature|=temp_low;
    Temper=temperature*0.0625;
}

void GetTemp(void){
        Init();
        Skip();
        Convert();
        DelayNus(60000);
        DelayNus(60000);
        DelayNus(60000);//延时1s以上
        Init();
        Skip();
        ReadDo();
        ReadTemp();
}

void InitLcd(void){
  LCDCTL = LCDON + LCD4MUX + LCDSG0_1;      // LCD on, 4-Mux, segments S0-S15
  BTCTL = BT_fLCD_DIV128;                   // LCD clock freq is ACLK/128
  P5SEL = 0xFC;                             // Select P5.2-7 as Com and Rxx
}
void display_number(unsigned long value, int start, int width)
{
    int i;
    for (i = 0;  i < width;  i++)
    {
        LCDMEM[7 + i - start] = digit[value%10]; // remainder = character in table to display
        value /= 10;
    }
}
void Lcd_Clr(void)
{
  volatile unsigned char i;
  for (i=0; i<7; i++)
  {
    LCDMEM = 0;
  }
}
void main(void)
{
    WDTCTL = WDTPW + WDTHOLD; // 停狗
    P4DIR |=BIT4;
    DQ1;
    InitLcd();
    Lcd_Clr();

    while(1)
        {
            GetTemp();
            display_number((unsigned long int)(Temper*1000),7,5);
            LCDMEM[3] |= SEGH;
        }
}