Datasheet

PIC18F46J50 FAMILY
DS39931D-page 132  2011 Microchip Technology Inc.
10.1 I/O Port Pin Capabilities
When developing an application, the capabilities of the
port pins must be considered. Outputs on some pins
have higher output drive strength than others. Similarly,
some pins can tolerate higher than V
DD input levels.
10.1.1 PIN OUTPUT DRIVE
General purpose output buffers are implemented with
CMOS transistors, for rail to rail output capability, when
lightly loaded. The output pin drive strengths vary for
groups of pins intended to meet the needs for a variety
of applications. PORTB and PORTC are designed to
drive higher loads, such as LEDs. All other ports are
designed for small loads; typically, indication only.
Table 10-1 summarizes the output capabilities. Refer to
Section 30.0 “Electrical Characteristics” for more
details.
TABLE 10-1: OUTPUT DRIVE LEVELS
10.1.2 INPUT PINS AND VOLTAGE
CONSIDERATIONS
The voltage tolerance of pins used as device inputs is
dependent on the pin’s input function. Pins that are used
as digital only inputs are able to handle DC voltages up to
5.5V; a level typical for digital logic circuits. In contrast,
pins that also have analog input functions of any kind can
only tolerate voltages up to V
DD. Voltage excursions
beyond V
DD on these pins should be avoided. Table 10-2
summarizes the input capabilities. Refer to Section 30.0
“Electrical Characteristics” for more details.
TABLE 10-2: INPUT VOLTAGE LEVELS
Port Drive Description
PORTA
(except RA6)
Minimum Intended for indication.
PORTD
PORTE
PORTB
High
Suitable for strong LED
drive levels.
PORTC
PORTA<6>
Port or Pin
Tolerated
Input
Description
PORTA<7:0>
V
DD
Only VDD input levels
are tolerated.
PORTB<3:0>
PORTC<2:0>
PORTE<2:0>
PORTB<7:4>
5.5V
Tolerates input levels
above V
DD, useful for
most standard logic.
PORTC<7:6>
PORTD<7:0>
PORTC<5:4> (USB) Designed for USB
specifications.