PIC18F23K20_10 Datasheet, PDF (291/456 Pages) Microchip Technology – 28/40/44-Pin Flash Microcontrollers with nanoWatt XLP Technology

PIC18F2XK20/4XK20
FIGURE 21-2:
VOLTAGE REFERENCE OUTPUT BUFFER EXAMPLE
PIC18F2XK20/4XK20
CVREF
Module
R⁽¹⁾
Voltage
Reference
Output
Impedance
CVREF
+
–
Buffered CVREF Output
Note 1: R is dependent upon the voltage reference Configuration bits, CVR<3:0> and CVRR.
REGISTER 21-1: CVRCON: COMPARATOR VOLTAGE REFERENCE CONTROL REGISTER
R/W-0
CVREN
bit 7
R/W-0
CVROE⁽¹⁾
R/W-0
CVRR
R/W-0
CVRSS
R/W-0
CVR3
R/W-0
CVR2
R/W-0
CVR1
R/W-0
CVR0
bit 0
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
bit 7
bit 6
bit 5
bit 4
bit 3-0
CVREN: Comparator Voltage Reference Enable bit
1 = CVREF circuit powered on
0 = CVREF circuit powered down
CVROE: Comparator VREF Output Enable bit⁽¹⁾
1 = CVREF voltage level is also output on the CVREF pin
0 = CVREF voltage is disconnected from the CVREF pin
CVRR: Comparator VREF Range Selection bit
1 = 0 to 0.667 CVRSRC, with CVRSRC/24 step size (low range)
0 = 0.25 CVRSRC to 0.75 CVRSRC, with CVRSRC/32 step size (high range)
CVRSS: Comparator VREF Source Selection bit
1 = Comparator reference source, CVRSRC = (VREF+) – (VREF-)
0 = Comparator reference source, CVRSRC = VDD – VSS
CVR<3:0>: Comparator VREF Value Selection bits (0  (CVR<3:0>)  15)
When CVRR = 1:
CVREF = ((CVR<3:0>)/24)  (CVRSRC) + VREF-
When CVRR = 0:
CVREF = (CVRSRC/4) + ((CVR<3:0>)/32)  (CVRSRC) + VREF-
Note 1: CVROE overrides the TRISA<2> bit setting.
 2010 Microchip Technology Inc.
DS41303G-page 291