PIC24HJ64 Datasheet

PIC24HJ32GP302/304, PIC24HJ64GPX02/X04, AND PIC24HJ128GPX02/X04
10.1.1 OPEN-DRAIN CONFIGURATION
In addition to the PORT, LAT and TRIS registers for
data control, some port pins 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 open-drain feature allows the generation of
outputs higher than VDD (e.g., 5V) on any desired
digital-only pins by using external pull-up resistors.
The maximum open-drain voltage allowed is the same
as the maximum VIH specification.
Some I/O pins may have internal analog functionality
that will not be shown on the device pin diagram.
These pins must be treated as analog pins. Table 10-1
lists all available pins and their functionality.
TABLE 10-1: AVAILABLE I/O PINS AND THEIR FUNCTIONALITY
I/O Pin Digital Only/5V Tolerant I/O Pin Digital Only/5V Tolerant
RA0 No RB9 Yes
RA1 No RB10 Yes
RA2 No RB11 Yes
RA3 No RB12 No
RA4 No RB13 No
RA7 Yes RB14 No
RA8 Yes RB15 No
RA9 Yes RC0 No
RA10 Yes RC1 No
RB0 No RC2 No
RB1 No RC3 Yes
RB2 No RC4 Yes
RB3 No RC5 Yes
RB4 No RC6 Yes
RB5 Yes RC7 Yes
RB6 Yes RC8 Yes
RB7 Yes RC9 Yes
RB8
Yes
10.2 Configuring Analog Port Pins
The AD1PCFGL and TRIS registers control the operation
of the analog-to-digital (A/D) port pins. The port
pins that are to function 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)
is converted.
When the PORT register is read, all pins configured as
analog input channels are read as cleared (a low level).
Pins configured as digital inputs do not convert an
analog input. Analog levels on any pin defined as a
digital input (including the ANx pins) can cause the
input buffer to consume current that exceeds the
device specifications.
10.2.1 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 an NOP, as shown in Example 10-1.
DS70293B-page 126 Preliminary © 2008 Microchip Technology Inc.