Datasheet

Table Of Contents
28
8493A–AVR–02/12
XMEGA C4
14. I/O Ports
14.1 Features
34 general purpose input and output pins with individual configuration
Output driver with configurable driver and pull settings:
Totem-pole
Wired-AND
–Wired-OR
Bus-keeper
Inverted I/O
Input with synchronous and/or asynchronous sensing with interrupts and events
Sense both edges
Sense rising edges
Sense falling edges
Sense low level
Optional pull-up and pull-down resistor on input and Wired-OR/AND configurations
Optional slew rate control
Asynchronous pin change sensing that can wake the device from all sleep modes
Two port interrupts with pin masking per I/O port
Efficient and safe access to port pins
Hardware read-modify-write through dedicated toggle/clear/set registers
Configuration of multiple pins in a single operation
Mapping of port registers into bit-accessible I/O memory space
Peripheral clocks output on port pin
Real-time counter clock output to port pin
Event channels can be output on port pin
Remapping of digital peripheral pin functions
Selectable USART, SPI, and timer/counter input/output pin locations
14.2 Overview
One port consists of up to eight port pins: pin 0 to 7. Each port pin can be configured as input or
output with configurable driver and pull settings. They also implement synchronous and asyn-
chronous input sensing with interrupts and events for selectable pin change conditions.
Asynchronous pin-change sensing means that a pin change can wake the device from all sleep
modes, included the modes where no clocks are running.
All functions are individual and configurable per pin, but several pins can be configured in a sin-
gle operation. The pins have hardware read-modify-write (RMW) functionality for safe and
correct change of drive value and/or pull resistor configuration. The direction of one port pin can
be changed without unintentionally changing the direction of any other pin.
The port pin configuration also controls input and output selection of other device functions. It is
possible to have both the peripheral clock and the real-time clock output to a port pin, and avail-
able for external use. The same applies to events from the event system that can be used to
synchronize and control external functions. Other digital peripherals, such as USART, SPI, and
timer/counters, can be remapped to selectable pin locations in order to optimize pin-out versus
application needs.
The notation of the ports are PORTA, PORTB, PORTC, PORTD, PORTE, and PORTR.