PIC16F570 datasheet(27/129 Pages) MICROCHIP

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 2013-2014 Microchip Technology Inc.

DS40001684E-page 27

PIC16F570

6.0

I/O PORT

As with any other register, the I/O register(s) can be

written and read under program control. However, read

instructions (e.g., MOVF PORTB,W) always read the I/O

pins independent of the pin’s Input/Output modes. On

Reset, all I/O ports are defined as input (inputs are at high-

impedance) since the I/O control registers are all set.

6.1

PORTA

PORTA is an 8-bit I/O register. The Configuration

Word can set several I/Os to alternate functions. When

acting as alternate functions, the pins will read as ‘0’

during a port read.

6.2

PORTB

PORTB is an 8-bit I/O register. The PORTB pins can be

configured with weak pull-ups and also for wake-up on

change. The wake-up on change and weak pull-up

functions are not pin-selectable.

6.3

PORTC

PORTC is an 8-bit I/O register.

6.4

TRIS Register

The Output Driver Control register is loaded with the

contents of the W register by executing the TRIS

instruction. A ‘1’ from a TRIS register bit puts the

corresponding output driver in a High-Impedance

mode. A ‘0’ puts the contents of the output data latch

on the selected pins, enabling the output buffer. The

only exception is the T0CKI pin, which may be

controlled by the OPTION register (see Register 4-2).

TRIS registers are “write-only”. Active bits in these

registers are set (output drivers disabled) upon Reset.

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