Datasheet

dsPIC33EPXXX(GP/MC/MU)806/810/814 and PIC24EPXXX(GP/GU)810/814
DS70616F-page 446 Preliminary © 2009-2012 Microchip Technology Inc.
REGISTER 25-6: CVRCON: COMPARATOR VOLTAGE REFERENCE CONTROL REGISTER
U-0 U-0 U-0 U-0 U-0 R/W-0 R/W-0 R/W-0
— — — — — VREFSEL BGSEL<1:0>
bit 15 bit 8
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
CVREN CVROE
(1)
CVRR CVRSS CVR<3:0>
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 15-11 Unimplemented: Read as ‘0’
bit 10 VREFSEL: Voltage Reference Select bit
1 = CV
REFIN = VREF+
0 = CVREFIN is generated by the resistor network
bit 9-8 BGSEL<1:0>: Band Gap Reference Source Select bits
11 = IVREF = VREF+
(2)
10 = IVREF = 0.20V (nominal)
01 = IV
REF = 0.60V (nominal)
00 = IVREF = 2.20V (nominal)
bit 7 CVREN: Comparator Voltage Reference Enable bit
1 = Comparator voltage reference circuit powered on
0 = Comparator voltage reference circuit powered down
bit 6 CVROE: Comparator Voltage Reference Output Enable bit
(1)
1 = Voltage level is output on CVREF pin
0 = Voltage level is disconnected from CV
REF pin
bit 5 CVRR: Comparator Voltage Reference Range Selection bit
1 = CVRSRC/24 step size
0 = CVRSRC/32 step size
bit 4 CVRSS: Comparator Voltage Reference Source Selection bit
1 = Comparator voltage reference source, CV
RSRC = (VREF+) – (VREF-)
(2)
0 = Comparator voltage reference source, CVRSRC = AVDD – AVSS
bit 3-0 CVR<3:0> Comparator Voltage Reference Value Selection 0 ≤ CVR<3:0> ≤ 15 bits
When CVRR =
1:
CVREFIN = (CVR<3:0>/24) • (CVRSRC)
When CVRR =
0:
CVREFIN = 1/4 • (CVRSRC) + (CVR<3:0>/32) • (CVRSRC)
Note 1: CVROE overrides the TRIS bit setting.
2: Selecting BGSEL<1:0> = 11 and CVRSS = 1 is invalid and will produce unpredictable results.