PIC24F16KL402 Datasheet, PDF (112/260 Pages) Microchip Technology – Low-Power, Low-Cost, General Purpose 16-Bit Flash Microcontrollers with nanoWatt XLP Technology

PIC24F16KL402 FAMILY
11.1.1 OPEN-DRAIN CONFIGURATION
In addition to the PORT, LAT and TRIS registers for
data control, each port pin can 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.
11.1.2 I/O PORT WRITE/READ TIMING
One instruction cycle is required between a port
direction change or port write operation and a read
operation of the same port. Typically, this instruction
would be a NOP.
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 PORTx 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 dig-
ital 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 A/D
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 and ANSB, Register 11-1 and Register 11-2).
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.
DS31037B-page 112
 2011 Microchip Technology Inc.