PIC24FV32KA304_1 Datasheet, PDF (140/320 Pages) Microchip Technology – 20/28/44/48-Pin, General Purpose, 16-Bit Flash Microcontrollers with XLP Technology

PIC24FV32KA304 FAMILY
11.1.1 OPEN-DRAIN CONFIGURATION
In addition to the PORT, LAT and TRIS registers for
data control, each port pin can also be individually
configured for either digital or open-drain output. This is
controlled by the Open-Drain Control register, ODCx,
associated with each port. Setting any of the bits
configures the corresponding pin to act as an
open-drain output.
The maximum open-drain voltage allowed is the same
as the maximum VIH specification.
11.2 Configuring Analog Port Pins
The use of the ANS and TRIS registers control the
operation of the A/D port pins. The port pins that are
desired as analog inputs must have their
corresponding TRIS bit set (input). If the TRIS bit is
cleared (output), the digital output level (VOH or VOL)
will be converted.
When reading the PORT register, all pins configured as
analog input channels will read as cleared (a low level).
Analog levels on any pin that is defined as a digital
input (including the ANx pins) may cause the input
buffer to consume current that exceeds the device
specifications.
11.2.1 ANALOG SELECTION REGISTER
I/O pins with shared analog functionality, such as ADC
inputs and comparator inputs, must have their digital
inputs shut off when analog functionality is used. Note
that analog functionality includes an analog voltage
being applied to the pin externally.
To allow for analog control, the ANSx registers are
provided. There is one ANS register for each port
(ANSA, ANSB and ANSC). Within each ANSx register,
there is a bit for each pin that shares analog
functionality with the digital I/O functionality.
If a particular pin does not have an analog function, that
bit is unimplemented. See Register 11-1 to Register 11-3
for implementation.
REGISTER 11-1: ANSA: ANALOG SELECTION (PORTA)
U-0
U-0
U-0
U-0
U-0
U-0
U-0
U-0
—
—
—
—
—
—
—
—
bit 15
bit 8
U-0
U-0
U-0
U-0
R/W-1
R/W-1
R/W-1
R/W-1
—
—
—
—
ANSA3
ANSA2
ANSA1
ANSA0
bit 7
bit 0
Legend:
R = Readable bit
-n = Value at POR
U = Unimplemented bit, read as ‘0’
W = Writable bit
HSC = Hardware Settable/Clearable bit
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
bit 15-4
bit 3-0
Unimplemented: Read as ‘0’
ANSA<3:0>: Analog Select Control bits
1 = Digital input buffer is not active (use for analog input)
0 = Digital input buffer is active
DS39995B-page 140
 2011 Microchip Technology Inc.