Z8F082ASH020SC datasheet(50/244 Pages) ZILOG

50 / 244 page

PS024705-0405

P R E L I M I N A R Y

General-Purpose I/O

Z8 Encore! XP® F08xA Series

Product Specification

Figure 6.GPIO Port Pin Block Diagram

GPIO Alternate Functions

Many of the GPIO port pins can be used for general-purpose I/O and access to on-chip

peripheral functions such as the timers and serial communication devices. The Port A–D

Alternate Function sub-registers configure these pins for either General-Purpose I/O or

alternate function operation. When a pin is configured for alternate function, control of the

port pin direction (input/output) is passed from the Port A–D Data Direction registers to

the alternate function assigned to this pin. Table 14 on page 34 lists the alternate functions

possible with each port pin. The alternate function associated at a pin is defined through

Alternate Function Sets sub-registers AFS1 and AFS2.

The crystal oscillator functionality is not controlled by the GPIO block. When the crystal

oscillator is enabled in the oscillator control block, the GPIO functionality of PA0 and PA1

is overridden. In that case, those pins function as input and output for the crystal oscillator.

PA0 and PA6 contain two different timer functions, a timer input and a complementary

timer output. Both of these functions require the same GPIO configuration, the selection

between the two is based on the timer mode. See “Timers” on page 58 for more details.

GND

VDD

Port Output Control

Port Data Direction

Port Output

Data Register

Port Input

Data Register

Port

DATA

Bus

System

Clock

System

Clock

Schmitt Trigger

Z8F082ASH020SC Datasheet(PDF) 50 Page - Zilog, Inc.