溫度信息的采集與顯示電路如所示,可以看到DS18B20數據口接在了單片機的P22上。在LCD第二行顯示"temp:",后面跟溫度,第一行不顯示。 使用元件:51單片機+DS18B20+LCD1602
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2022-11-16 15:36 上傳
單片機源程序如下:
- #include <reg52.H>
- #include <intrins.H>
- #include <math.H>
- #define uchar unsigned char
- #define uint unsigned int
- sbit dula = P2^6;
- sbit wela = P2^7;
- sbit rw = P3^6;
- sbit RS = P3^5;
-
- sbit LCDEN = P3^4;
- void delayUs()
- {
- _nop_();
- }
- void delayMs(uint a)
- {
- uint i, j;
- for(i = a; i > 0; i--)
- for(j = 100; j > 0; j--);
- }
- void writeComm(uchar comm)
- {
- RS = 0;
- P0 = comm;
- LCDEN = 1;
- delayUs();
- LCDEN = 0;
- delayMs(1);
- }
- //寫數據:RS=1, RW=0;
- void writeData(uchar dat)
- {
- RS = 1;
- P0 = dat;
- LCDEN = 1;
- delayUs();
- LCDEN = 0;
- delayMs(1);
- }
- void init()
- {
- rw = 0;
- dula = wela = 0;
- writeComm(0x38);
- writeComm(0x0c);
- writeComm(0x06);
- writeComm(0x01);
- }
- void writeString(uchar * str, uchar length)
- {
- uchar i;
- for(i = 0; i < length; i++)
- {
- writeData(str[i]);
- }
- }
-
- /**//*****************************DS18B20*******************************/
- sbit ds = P2^2;
- void dsInit()
- {
-
- unsigned int i;
- ds = 0;
- i = 100;
- while(i>0) i--;
- ds = 1;
- i = 4;
- while(i>0) i--;
- }
-
- void dsWait()
- {
- unsigned int i;
- while(ds);
- while(~ds);
- i = 4;
- while(i > 0) i--;
- }
- bit readBit()
- {
- unsigned int i;
- bit b;
- ds = 0;
- i++;
- ds = 1;
- i++; i++;
- b = ds;
- i = 8;
- while(i>0) i--;
- return b;
- }
- unsigned char readByte()
- {
- unsigned int i;
- unsigned char j, dat;
- dat = 0;
- for(i=0; i<8; i++)
- {
- j = readBit();
-
- dat = (j << 7) | (dat >> 1);
- }
- return dat;
- }
- void writeByte(unsigned char dat)
- {
- unsigned int i;
- unsigned char j;
- bit b;
- for(j = 0; j < 8; j++)
- {
- b = dat & 0x01;
- dat >>= 1;
-
- if(b)
- {
- ds = 0; i++; i++;
- ds = 1;
- i = 8; while(i>0) i--;
- }
- else
- {
- ds = 0;
- i = 8; while(i>0) i--;
- ds = 1;
- i++; i++;
- }
- }
- }
- void sendChangeCmd()
- {
- dsInit();
- dsWait();
- delayMs(1);
- writeByte(0xcc);
- writeByte(0x44);
- }
- void sendReadCmd()
- {
- dsInit();
- dsWait();
- delayMs(1);
- writeByte(0xcc);
- writeByte(0xbe);
- }
- int getTmpValue()
- {
- unsigned int tmpvalue;
- int value;
- float t;
- unsigned char low, high;
- sendReadCmd();
-
- low = readByte();
- high = readByte();
-
- tmpvalue = high;
- tmpvalue <<= 8;
- tmpvalue |= low;
- value = tmpvalue;
-
- \
- t = value * 0.0625;
- \
- value = t * 100 + (value > 0 ? 0.5 : -0.5); //大于0加0.5, 小于0減0.5
- return value;
- }
- void display(int v)
- {
- unsigned char count;
- unsigned char datas[] = {0, 0, 0, 0, 0};
- unsigned int tmp = abs(v);
- datas[0] = tmp / 10000;
- datas[1] = tmp % 10000 / 1000;
- datas[2] = tmp % 1000 / 100;
- datas[3] = tmp % 100 / 10;
- datas[4] = tmp % 10;
- writeComm(0xc0+6); //第二行開頭顯示0xc0+0 第二行末尾顯示0xc0+10
- //第一行緊跟0x80+6
- //第二行緊跟0xc0+6
- if(v < 0)
- {
- writeString("- ", 1);
- }
- else
- {
- writeString("+ ", 1);
- }
- if(datas[0] != 0)
- {
- writeData('0'+datas[0]);
- }
- for(count = 1; count != 5; count++)
- {
- writeData('0'+datas[count]);
- if(count == 2)
- {
- writeData('.');
- }
- }
- }
- /**//*****************************DS18B20*******************************/
- void main()
- {
- uchar table[] = "temp:"; //temp: temperature:
- sendChangeCmd();
- init();
- writeComm(0xc0);
- writeComm(0xc0); //一行0x80 二行0xc0
- writeString(table,5); //5 12
- while(1)
- {
- delayMs(1000); //溫度轉換時間需要750ms以上
- writeComm(0xc0);
- display(getTmpValue());
- sendChangeCmd();
- }
- }
復制代碼
Keil代碼與Proteus8.13版本的仿真下載(注意:不能兼容其他版本 只能用8.13打開):
溫度18B20與IIC總線.zip
(97.17 KB, 下載次數: 20)
2022-11-16 15:37 上傳
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