Datasheet

PIC18F1230/1330
DS39758D-page 184  2009 Microchip Technology Inc.
REGISTER 18-1: CVRCON: COMPARATOR VOLTAGE REFERENCE CONTROL REGISTER
R/W-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CVREN — CVRR CVRSS CVR3 CVR2 CVR1 CVR0
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 CVREN: Comparator Voltage Reference Enable bit
1 =CV
REF circuit powered on
0 =CV
REF circuit powered down
bit 6 Unimplemented: Read as ‘0’
bit 5 CVRR: Comparator V
REF Range Selection bit
1 = 0 to 0.667 CVRSRC, with CVRSRC/24 step size (low range)
0 = 0.25 CV
RSRC to 0.75 CVRSRC, with CVRSRC/32 step size (high range)
bit 4 CVRSS: Comparator VREF Source Selection bit
When CVRR =
1
1 = Comparator reference source, CVRSRC = (VREF+) – (AVSS)
0 = Comparator reference source, CV
RSRC = AVDD – AVSS
When CVRR = 0
1 =VREF+ input used directly, comparator voltage reference bypassed
0 = No reference is provided
bit 3-0 CVR3:CVR0: Comparator V
REF Value Selection bits (0  (CVR3:CVR0)  15)
When CVRR = 1:
CV
REF = ((CVR3:CVR0)/24)  (CVRSRC)
When CVRR = 0:
CV
REF = (CVRSRC/4) + ((CVR3:CVR0)/32)  (CVRSRC)