78 lines
1.4 KiB
C
78 lines
1.4 KiB
C
/* # 单总线代码片段说明
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1. 本文件夹中提供的驱动代码供参赛选手完成程序设计参考。
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2.
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参赛选手可以自行编写相关代码或以该代码为基础，根据所选单片机类型、运行速度和试题
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中对单片机时钟频率的要求，进行代码调试和修改。
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*/
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#include "onewire.h"
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sbit DQ = P1 ^ 4;
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//
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void Delay_OneWire(unsigned int t) {
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unsigned char i;
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while (t--) {
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for (i = 0; i < 12; i++);
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}
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}
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//
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void Write_DS18B20(unsigned char dat) {
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unsigned char i;
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for (i = 0; i < 8; i++) {
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DQ = 0;
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DQ = dat & 0x01;
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Delay_OneWire(5);
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DQ = 1;
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dat >>= 1;
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}
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Delay_OneWire(5);
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}
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//
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unsigned char Read_DS18B20(void) {
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unsigned char i;
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unsigned char dat;
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for (i = 0; i < 8; i++) {
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DQ = 0;
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dat >>= 1;
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DQ = 1;
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if (DQ) {
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dat |= 0x80;
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}
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Delay_OneWire(5);
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}
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return dat;
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}
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//
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bit init_ds18b20(void) {
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bit initflag = 0;
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DQ = 1;
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Delay_OneWire(12);
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DQ = 0;
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Delay_OneWire(80);
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DQ = 1;
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Delay_OneWire(10);
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initflag = DQ;
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Delay_OneWire(5);
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return initflag;
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}
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float rd_temperature() {
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unsigned char low, high;
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init_ds18b20();
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Write_DS18B20(0xcc);
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Write_DS18B20(0x44);
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Delay_OneWire(200);
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init_ds18b20();
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Write_DS18B20(0xcc);
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Write_DS18B20(0xbe);
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low = Read_DS18B20();
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high = Read_DS18B20();
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return (float)(high << 8 | low) * 0.0625;
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}
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