PIC18F2221 MICROCHIP [Microchip Technology], PIC18F2221 Datasheet - Page 236

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

PIC18F4321 FAMILY
19.4
The selection of the automatic acquisition time and A/D
conversion clock is determined in part by the clock
source and frequency while in a power-managed mode.
If the A/D is expected to operate while the device is in
a power-managed mode, the ACQT2:ACQT0 and
ADCS2:ADCS0 bits in ADCON2 should be updated in
accordance with the clock source to be used in that
mode. After entering the mode, an A/D acquisition or
conversion may be started. Once started, the device
should continue to be clocked by the same clock
source until the conversion has been completed.
If desired, the device may be placed into the
corresponding Idle mode during the conversion. If the
device clock frequency is less than 1 MHz, the A/D RC
clock source should be selected.
Operation in Sleep mode requires the A/D F
be selected. If bits ACQT2:ACQT0 are set to ‘000’ and
a conversion is started, the conversion will be delayed
one instruction cycle to allow execution of the SLEEP
instruction and entry to Sleep mode. The IDLEN bit
(OSCCON<7>) must have already been cleared prior
to starting the conversion.
DS39689E-page 234
Operation in Power-Managed
Modes
RC
clock to
Preliminary
19.5
The ADCON1, TRISA, TRISB and TRISE registers all
configure the A/D port pins. The port pins needed as
analog inputs must have their corresponding TRIS bits
set (input). If the TRIS bit is cleared (output), the digital
output level (V
The A/D operation is independent of the state of the
CHS3:CHS0 bits and the TRIS bits.
Note 1: When reading the Port register, all pins
2: Analog levels on any pin defined as a
3: The
Configuring Analog Port Pins
configured as analog input channels will
read as cleared (a low level). Pins
configured as digital inputs will convert as
analog inputs. Analog levels on a digitally
configured
converted.
digital input may cause the digital input
buffer to consume current out of the
device’s specification limits.
Register 3H configures PORTB pins to
reset as analog or digital pins by control-
ling how the PCFG<3:0> bits in ADCON1
are reset.
OH
or V
PBADEN
OL
© 2007 Microchip Technology Inc.
) will be converted.
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