Datasheet

 2010 Microchip Technology Inc. DS39616D-page 241

PIC18F2331/2431/4331/4431

R/W-0 R/W-0 U-0 R/W-0 R-0 R-0 R-0 R-0

VCFG1 VCFG0

— FIFOEN BFEMT BFOVL ADPNT1 ADPNT0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7-6 VCFG<1:0>: A/D V

REF+ and A/D VREF- Source Selection bits

00 =V

REF+ = AVDD, VREF- = AVSS (AN2 and AN3 are analog inputs or digital I/O)

01 =V

REF+ = External VREF+, VREF- = AVSS (AN2 is an analog input or digital I/O)

10 =V

REF+ = AVDD, VREF- = External VREF- (AN3 is an analog input or digital I/O)

11 =V

REF+ = External VREF-, VREF- = External VREF-

bit 5 Unimplemented: Read as ‘0’

bit 4 FIFOEN: FIFO Buffer Enable bit

1 = FIFO is enabled

0 = FIFO is disabled

bit 3 BFEMT: Buffer Empty bit

1 = FIFO is empty

0 = FIFO is not empty (at least one of four locations has unread A/D result data)

bit 2 BFOVFL: Buffer Overflow bit

1 = A/D result has overwritten a buffer location that has unread data

0 = A/D result has not overflowed

bit 1-0 ADPNT<1:0>: Buffer Read Pointer Location bits

Designates the location to be read next.

00 = Buffer Address 0

01 = Buffer Address 1

10 = Buffer Address 2

11 = Buffer Address 3