第十二届蓝桥杯单片机真题

#include <REGX52.H> #include <intrins.h> #include "NIXIE.H" #include "SYSTEM.H" sbit scl=P2^0; sbit sda=P2^1; #define DELAY_TIME 10 #define PCF8591_ADDRESS 0x90 float DAC_Volt=0; float Output_Volt=0; unsigned char Flag=0; static void I2C_Delay(unsigned char n) { do { _nop_();_nop_();_nop_();_nop_();_nop_(); _nop_();_nop_();_nop_();_nop_();_nop_(); _nop_();_nop_();_nop_();_nop_();_nop_(); } while(n--); } // void I2CStart(void) { sda = 1; scl = 1; I2C_Delay(DELAY_TIME); sda = 0; I2C_Delay(DELAY_TIME); scl = 0; } // void I2CStop(void) { sda = 0; scl = 1; I2C_Delay(DELAY_TIME); sda = 1; I2C_Delay(DELAY_TIME); } // void I2CSendByte(unsigned char byt) { unsigned char i; for(i=0; i<8; i++){ scl = 0; I2C_Delay(DELAY_TIME); if(byt & 0x80){ sda = 1; } else{ sda = 0; } I2C_Delay(DELAY_TIME); scl = 1; byt <<= 1; I2C_Delay(DELAY_TIME); } scl = 0; } // unsigned char I2CReceiveByte(void) { unsigned char da; unsigned char i; for(i=0;i<8;i++){ scl = 1; I2C_Delay(DELAY_TIME); da <<= 1; if(sda) da |= 0x01; scl = 0; I2C_Delay(DELAY_TIME); } return da; } // unsigned char I2CWaitAck(void) { unsigned char ackbit; scl = 1; I2C_Delay(DELAY_TIME); ackbit = sda; scl = 0; I2C_Delay(DELAY_TIME); return ackbit; } // void I2CSendAck(unsigned char ackbit) { scl = 0; sda = ackbit; I2C_Delay(DELAY_TIME); scl = 1; I2C_Delay(DELAY_TIME); scl = 0; sda = 1; I2C_Delay(DELAY_TIME); } void Write_Data(unsigned char Command,unsigned char Data) { I2CStart(); I2CSendByte(PCF8591_ADDRESS); I2CWaitAck(); I2CSendByte(Command); I2CWaitAck(); I2CSendByte(Data); I2CWaitAck(); I2CStop(); } unsigned char PCF8591_ReadData(unsigned char Command) { unsigned char Data; I2CStart(); I2CSendByte(PCF8591_ADDRESS); I2CWaitAck(); I2CSendByte(Command); I2CWaitAck(); I2CStart(); I2CSendByte(PCF8591_ADDRESS|0x01); I2CWaitAck(); Data=I2CReceiveByte(); I2CSendAck(1); I2CStop(); return Data; } void DAC_PROCESS() { if(Mode==1) { if(Temperature>(ParaT*100)) { Write_Data(0x41,5); Flag=1; } else { Write_Data(0x41,0); Flag=2; } } if(Mode==2) { if(Temperature>=4000) { Output_Volt=4.0; } else if(Temperature<=1000) { Output_Volt=1.0; } else { DAC_Volt=(3.0/20)*(float)(Temperature)-200; Output_Volt=DAC_Volt/100; } Write_Data(0x41,Output_Volt); } }