Datasheet

 2010-2012 Microchip Technology Inc. DS39977F-page 251
PIC18F66K80 FAMILY
18.9 Measuring Temperature with the
CTMU Module
The CTMU, along with an internal diode, can be used
to measure the temperature. The A/D can be con-
nected to the internal diode and the CTMU module can
source the current to the diode. The A/D reading will
reflect the temperature. With the increase, the A/D
readings will go low. This can be used for low-cost
temperature measurement applications.
EXAMPLE 18-6: ROUTINE FOR TEMPERATURE MEASUREMENT USING INTERNAL DIODE
// Initialize CTMU
CTMUICON = 0x03;
CTMUCONHbits.CTMUEN = 1;
CTMUCONLbits.EDG1STAT = 1;
// Initialize ADC
ADCON0 = 0xE5; // Enable ADC and connect to Internal diode
ADCON1 = 0x00;
ADCON2 = 0xBE; //Right Justified
ADCON0bits.GO = 1; // Start conversion
while(ADCON0bits.G0);
Temp = ADRES; // Read ADC results (inversely proportional to temperature)
Note: The temperature diode is not calibrated or standardized; the user must calibrate the diode to their application.