串口發(fā)送溫度給上位機

1、====DS18B20實現(xiàn)溫度轉(zhuǎn)換。當(dāng)MCU接收到上位機發(fā)送的01時，將當(dāng)前溫度返回上位機============#include#include#defineuunsigned#defineuintunsignedintsbitDS=P2^2溫度傳感器信號線uinttempnuasignalttime0_1sbflagflag_onsbitdula=P2^6sbitwela=P2^7sbitbeep=P2^3ucodetable[]=

2、0x3f0x060x5b0x4f0x660x6d0x7d0x070x7f0x6f不帶小數(shù)的0~9編碼0xbf0x860xdb0xcf0xe60xed0xfd0x870xff0xef帶小數(shù)的0~9編碼voiddelay(uintcount)delayuintijf(i=counti0i)f(j=110j0j)voiddsreset(void)DS18B20初始化1，先將數(shù)據(jù)線置高電平uinti2，延時要求不嚴(yán)格但盡可能短些DS=03，將數(shù)

3、據(jù)線置低電平i=1034，延時（480~960微秒）while(i0)i5，將數(shù)據(jù)線置高電平DS=16，延時（15~60微秒）DS18B20返回低電平確定它的存在i=47，CPU讀到低電平并延時最少480微秒while(i0)i8，將數(shù)據(jù)線置高電平bittmpreadbit(void)讀一位數(shù)據(jù)1，將數(shù)據(jù)線拉高uinti2，延時2微秒bitdat3，將數(shù)據(jù)線拉低DS=0ii起延時作用DS=1ii4，延時6微秒dat=DS5，將數(shù)據(jù)線拉高

4、voidtmpchange(void)DS18B20beginchangedsreset()delay(1)tmpwritebyte(0xcc)忽略ROM地址（一個從機工作時）tmpwritebyte(0x44)溫度轉(zhuǎn)換uinttmp()讀取寄存器中存儲的溫度數(shù)據(jù)floatttuabdsreset()delay(1)tmpwritebyte(0xcc)tmpwritebyte(0xbe)讀內(nèi)部RAM中9字節(jié)的溫度數(shù)據(jù)a=tmpread(

5、)讀低8位b=tmpread()讀高8位temp=btemp=8兩個字節(jié)組成一個字節(jié)temp=temp|att=temp0.0625溫度在寄存器中為12位，分辨率為0.0625temp=tt100.5乘以10表示小數(shù)點后只取一位，加0.5是四舍五入returntempvoiddisplay(unumuinfmation)顯示程序ukdula=1P0=table[infmation]dula=0P0=0xffwela=1k=~((0x01