Datasheet

PIC14000
DS40122B-page 60
Preliminary
 1996 Microchip Technology Inc.
8.4 A/D Comparator
The PIC14000 includes a high gain comparator for
A/D conversions. The positive input terminal of the A/D
comparator is connected to the output of an analog
mux through an RC low-pass filter. The nominal
time-constant for the RC filter is 3.5 µ s. The negative
input terminal is connected to the external 0.1 µ F (nom-
inal) ramp capacitor.
8.5 Analog Mux
A total of 16 channels are internally multiplexed to the
single A/D comparator positive input. Four
configuration bits (ADCON0<7:4>) select the channel
to be converted. Refer to Table 8-1 for channel assign-
ments.
TABLE 8-1: A/D CHANNEL ASSIGNMENT
ADCON0(7:4) A/D Channel
0000RA0/AN0 pin
0001RA1/AN1 pin
0010RA2/AN2 pin
0011RA3/AN3 pin
0100Bandgap reference voltage
0101Slope reference SREFHI
0110Slope reference SREFLO
0111Internal temperature sensor
1000Programmable reference A output
1001Programmable reference B output
1010RD4/AN4 pin
1011RD5/AN5 pin
1100RD6/AN6 pin
1101RD7/AN7 pin
1110Reserved
1111Reserved