PIC18F97J60_11 Datasheet, PDF (353/492 Pages) Microchip Technology – 64/80/100-Pin, High-Performance, 1-Mbit Flash Microcontrollers with Ethernet

PIC18F97J60 FAMILY
23.9 Analog Input Connection
Considerations
A simplified circuit for an analog input is shown in
Figure 23-4. Since the analog pins are connected to a
digital output, they have reverse biased diodes to VDD
and VSS. The analog input, therefore, must be between
VSS and VDD. If the input voltage deviates from this
range by more than 0.6V in either direction, one of the
diodes is forward biased and a latch-up condition may
occur. A maximum source impedance of 10 k is
recommended for the analog sources. Any external
component connected to an analog input pin, such as
a capacitor or a Zener diode, should have very little
leakage current.
FIGURE 23-4:
COMPARATOR ANALOG INPUT MODEL
VDD
RS < 10k
VT = 0.6V
RIC
AIN
VA
CPIN
5 pF
VT = 0.6V
ILEAKAGE
±500 nA
Comparator
Input
VSS
Legend:
CPIN
=
VT
=
ILEAKAGE =
RIC
=
RS
=
VA
=
Input Capacitance
Threshold Voltage
Leakage Current at the pin due to various junctions
Interconnect Resistance
Source Impedance
Analog Voltage
TABLE 23-1: REGISTERS ASSOCIATED WITH COMPARATOR MODULE
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on Page:
INTCON GIE/GIEH PEIE/GIEL TMR0IE INT0IE
RBIE TMR0IF INT0IF
RBIF
69
PIR2
OSCFIF CMIF
ETHIF
r
BCL1IF
—
TMR3IF CCP2IF
71
PIE2
OSCFIE
CMIE
ETHIE
r
BCL1IE
—
TMR3IE CCP2IE
71
IPR2
OSCFIP
CMIP
ETHIP
r
BCL1IP
—
TMR3IP CCP2IP
71
CMCON C2OUT C1OUT C2INV C1INV
CIS
CM2
CM1
CM0
70
CVRCON CVREN CVROE CVRR CVRSS CVR3 CVR2 CVR1
CVR0
70
PORTF
RF7
RF6
RF5
RF4
RF3
RF2
RF1
RF0
72
TRISF
TRISF7 TRISF6 TRISF5 TRISF4 TRISF3 TRISF2 TRISF1 TRISF0
71
Legend: — = unimplemented, read as ‘0’, r = reserved. Shaded cells are not used by the comparator module.
 2011 Microchip Technology Inc.
DS39762F-page 353