HCS08 datasheet(129/290 Pages) MOTOROLA

129 / 290 page

Data Sheet — MC9S08GB60/D V1.5

MOTOROLA

129

MC9S08GB/GT

Section 8 Parallel Input/Output

8.1 Introduction

This section explains software controls related to parallel input/output (I/O). The MC9S08GBxx has seven

I/O ports which include a total of 56 general-purpose I/O pins (one of these pins is output only). The

MC9S08GTxx has six I/O ports which include a total of up to 36 general-purpose I/O pins (one pin, PTG0,

is output only). See the Pins and Connections section for more information about the logic and hardware

aspects of these pins.

Many of these pins are shared with on-chip peripherals such as timer systems, external interrupts, or

keyboard interrupts. When these other modules are not controlling the port pins, they revert to

general-purpose I/O control. For each I/O pin, a port data bit provides access to input (read) and output

(write) data, a data direction bit controls the direction of the pin, and a pullup enable bit enables an internal

pullup device (provided the pin is configured as an input), and a slew rate control bit controls the rise and

fall times of the pins.

NOTE:

Not all general-purpose I/O pins are available on all packages. To avoid extra

current drain from floating input pins, the user’s reset initialization routine in the

application program should either enable on-chip pullup devices or change the

direction of unconnected pins to outputs so the pins do not float.

HCS08 데이터시트(PDF) 129 Page - Motorola, Inc