PIC18F2221 MICROCHIP [Microchip Technology], PIC18F2221 Datasheet - Page 243

• Manufacturer Part Number: PIC18F2221
• Description: 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

20.9
A simplified circuit for an analog input is shown in
Figure 20-4. Since the analog pins are connected to a
digital output, they have reverse biased diodes to V
and V
V
FIGURE 20-4:
TABLE 20-1:
© 2007 Microchip Technology Inc.
CMCON
CVRCON
INTCON
PIR2
PIE2
IPR2
PORTA
LATA
TRISA
Legend: — = unimplemented, read as ‘0’. Shaded cells are unused by the comparator module.
Note 1:
SS
Name
and V
SS
. The analog input, therefore, must be between
Analog Input Connection
Considerations
DD
PORTA<7:6> and their direction and latch bits are individually configured as port pins based on various
primary oscillator modes. When disabled, these bits read as ‘0’.
. If the input voltage deviates from this
VA
GIE/GIEH PEIE/GIEL TMR0IE
TRISA7
LATA7
OSCFIF
OSCFIE
OSCFIP
CVREN
C2OUT
RA7
Bit 7
REGISTERS ASSOCIATED WITH COMPARATOR MODULE
R
S
Legend:
(1)
(1)
< 10k
(1)
COMPARATOR ANALOG INPUT MODEL
TRISA6
A
LATA6
CVROE
C1OUT
IN
RA6
CMIF
CMIE
CMIP
Bit 6
C
V
I
R
R
VA
LEAKAGE
C
5 pF
(1)
T
PIN
IC
S
(1)
PIN
(1)
PORTA Data Latch Register (Read and Write to Data Latch)
PORTA Data Direction Control Register
C2INV
CVRR
Bit 5
RA5
= Input Capacitance
= Threshold Voltage
= Leakage Current at the pin due to various junctions
= Interconnect Resistance
= Source Impedance
= Analog Voltage
—
—
—
Preliminary
V
DD
CVRSS
INT0IE
C1INV
EEIE
EEIP
DD
Bit 4
EEIF
RA4
V
V
T
T
= 0.6V
= 0.6V
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 kΩ 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.
BCLIF
BCLIE
BCLIP
CVR3
RBIE
PIC18F4321 FAMILY
Bit 3
RA3
CIS
I
±500 nA
V
LEAKAGE
TMR0IF
HLVDIE
HLVDIP
SS
HLVDIF
CVR2
Bit 2
CM2
RA2
R
IC
TMR3IF
TMR3IE
TMR3IP
INT0IF
CVR1
Bit 1
CM1
RA1
CCP2IF
CCP2IE
CCP2IP
Comparator
Input
CVR0
DS39689E-page 241
Bit 0
RBIF
CM0
RA0
on page
Values
Reset
51
51
52
52
52
52
52
52
52