msp430f149控制DHT11温湿度传感器的串口程序

只看该作者 · 2011-10-7 17:01

哪位大侠写过msp430f149控制DHT11温室读传感器的串口显示程序，我调了好久总是不能显示数据？不知道什么原因？高手帮忙啊，不胜感激之至！！
串口程序;
#include  "usart.h"
struct DHT_data
{
unsigned char DH_H;    //湿度整数
unsigned char DH_L;    //湿度小数
unsigned char T_H;    //温度整数
unsigned char T_L;    //温度小数
unsigned char Checksum; //校验和
}DHT_data;
void Usart_Init(void)
{

P3SEL |= 0x30;                         // P3.4,5 = USCI_A0 TXD/RXD
ME1 |= UTXE0 + URXE0;                   // 使能USART0收发
UCTL0 |= CHAR;                         // 8-bit character
UTCTL0 |= SSEL0;                         // UCLK = ACLK
UBR00 = 0x03;                            // 32k/9600 - 3.41
UBR10 = 0x00;                            //
UMCTL0 = 0x4A;                            // Modulation
UCTL0 &= ~SWRST;                         // 初始化UART0状态机
IE1 |= URXIE0;                         // 使能接收中断
_EINT();
}
void TXString( char* string, int length )//发送字符串
{
  int pointer;
  for( pointer = 0; pointer < length; pointer++)
  {
volatile int i;
TXBUF0 = string[pointer];
while (!(IFG1 & UTXIFG0));
  }
}
void my_putchar(unsigned char ch)
{
  TXBUF0=(unsigned char) ch;
  while (!(IFG1 & UTXIFG0));

}
void my_puts(unsigned char *s)
{
  while(*s++)
my_putchar(*s);
}

DHT11 程序：

#include "dht11.h"
unsigned char humidity, temperature, check_sum ;
/**********************************************/
/*          开始 DHT11 温湿度计             */
/* 输入：无                */
/* 输出：应答标志  0：应答失败 1：应答成功  */
/**********************************************/
unsigned  char start_DHT11(void)
{
unsigned  char time=0;
DHT11_OUTPUT;
DHT11_H;
DHT11_L; //拉低18ms以上
delay_ms(30);
DHT11_H;
delay_us(40);
DHT11_INPUT;
// temp=DHT11_IN;
if(!DHT11_IN)
{
while(!(DHT11_IN)&&time++);
while(DHT11_IN&&time++);
return 1;
}
else
{
   return 0;
}
}
void read_DHT11(void)
{
unsigned char tem[5];    //读到的五个数
unsigned char i, j, temp;
for(i = 0; i < 5; i ++)
  {
   tem = 0;
   for(j = 0; j < 8; j ++)
   {
      tem *= 2; //不可用tem << 1 否则不移位
      temp = 2;    //
      delay_us(20); //先延20uS 再检查30uS
      while((!DHT11_IN) && temp ++)//避免死等
         if(temp == 2)
            break;
      delay_us(32); //高电平长于26-28uS为1否为0
      temp = 2;
      if(DHT11_IN)
      {
         while(DHT11_IN && temp ++) //当为1时等到低电平再进入下次循环。
            if(temp == 2)
               break;
         tem |= 0x01;
      }
      delay_us(5);
   }
humidity = tem[0];
temperature = tem[2];
check_sum = tem[4];
  }

}

主函数main：
#include <msp430x14x.h>
#include "dht11.h"
#include "usart.h"
const char word1[] = {"\r\n**DHT11 TEST**\r\n"};
const char word2[] = {"\r\n**DHT11 CHECK**\r\n"};
const char word3[] = {"\r\n**DHT11 NOT EXIST**\r\n"};
void display(void);
void  main( void )
{

  WDTCTL=WDTPW+WDTHOLD;       //关看门狗
  Usart_Init();
  P2DIR |=BIT7;//点亮LED0 RED
  P2OUT &=~BIT7;
  P2DIR |=BIT5;//点亮LED1 GREEN
  TXString((char*)word1, sizeof word1);
  delay_ms(1000);
  delay_ms(1000);
  while(1)
  {

if(start_DHT11())    //如果应答成功
{
   P2OUT |=BIT7;
   TXString((char*)word2, sizeof word2);
   read_DHT11(); //读温湿度

      display();       //则显示温湿度数值

}
else
{
   P2OUT &=~BIT7;
   TXString((char*)word3, sizeof word3);
}
P2OUT |=BIT5;
delay_ms(1000);
P2OUT&=~BIT5;
delay_ms(1000);
  }

}
void display(void)
{
unsigned char table[11];
table[0]=humidity/0x10+0x30;//湿度
table[1]=humidity%0x10+0x30;
table[2]='%';
table[3]='R';
table[4]='H';
table[5]=' ';
table[6]=temperature/0X10+0x30;//温度
table[7]=temperature%0X10+0x30;
table[8]='C';
table[9]='\r';
table[10]='\n';
TXString((char*)table, sizeof table);
}

需要的头文件：

usart.h

#ifndef _USART_H_
#define _USART_H_
#include"msp430x14x.h"
void Usart_Init(void);
void TXString( char* string, int length );//发送字符串
void my_putchar(unsigned char ch);
void my_puts(unsigned char *s);
#endif

dht11.h
#ifndef _DHT11_H_
#define _DHT11_H_
#include "msp430x14x.h"
#define CPU       (12000000)
#define delay_us(x) (__delay_cycles((double)x*CPU/1000000.0))
#define delay_ms(x) (__delay_cycles((double)x*CPU/1000.0))
#define DHT11_OUTPUT P1DIR|=BIT0
#define DHT11_INPUT P1DIR&=~BIT0
#define DHT11_H P1OUT|=BIT0
#define DHT11_L P1OUT&=~BIT0
#define DHT11_IN (P1IN&BIT0)
extern unsigned char humidity, temperature, check_sum ;
unsigned  char start_DHT11(void);
void read_DHT11(void);
#endif