ADT7301
The following software program shows how to program a
PIC16F873 to communicate with the ADT7301. The
PIC16F873 is configured as an SPI master with the Port A.1 pin
CS
used as . Any microchip microcontroller can use this
program by simply exchanging the include file for the device
that is being used.
#include <16F873.h>
#device adc = 8
#use delay(clock = 4000000)
#fuses NOWDT,XT, PUT, NOPROTECT, BROWNOUT, LVP
#BIT CKP = 0x14.4
#define CS PIN_A1
void main(){
int MSByte,LSByte;
long int ADC_Temp_Code;
float TempVal,ADC_Temp_Code_dec;
setup_spi(spi_master);
CKP = 1;
//Pic is set up as master device.
//Idle state of clock is high.
do{
delay_ms(10);
//Allow time for conversions.
Output_low(CS);
//Pull CS low.
delay_us(10);
MSByte = SPI_Read(0);
LSByte = SPI_Read(0);
//CS to SCLK set-up time.
//The first byte is clocked in.
//The second byte is clocked in.
delay_us(10);
Output_High(CS);
//SCLK to CS set-up time.
//Bring CS high.
ADC_Temp_Code = make16(MSByte,LSByte);
ADC_Temp_Code_dec = (float)ADC_Temp_Code;
//16 bit ADC code is stored ADC_Temp_Code.
//Convert to float for division.
if ((0x2000 & ADC_Temp_Code) == 0x2000)
//Check sign bit for negative value.
{
TempVal = (ADC_Temp_Code_dec - 16384)/32;
//Conversion formula if negative temperature.
}
else
{
TempVal = (ADC_Temp_Code_dec/32);
}
//Conversion formula if positive temperature.
//Temperature value stored in TempVal.
}while(True);
}
Rev. B | Page 13 of 16
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