SC9RS08KA2 datasheet(20/134 Pages) FREESCALE

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Chapter 2 Pins and Connections

SC9RS08KA2 Series Data Sheet, Rev. 1

Freescale Semiconductor

cables and the absolute value of the internal pullup device play almost no role in determining rise and fall

times on the BKGD pin.

2.4.4

General-Purpose I/O and Peripheral Ports

The remaining pins are shared among general-purpose I/O and on-chip peripheral functions such as timers

and analog comparator. Immediately after reset, all of these pins are configured as high-impedance

general-purpose inputs with internal pullup/pulldown devices disabled.

NOTE

To avoid extra current drain from floating input pins, the reset initialization

routine in the application program should either enable on-chip

pullup/pulldown devices or change the direction of unused pins to outputs.

Table 2-1. Pin Sharing Reference

Pin Name

Direction

Pullup/Pulldown1

1 SWC is software-controlled pullup/pulldown resistor; the register is associated with the respective port.

Alternative Functions2

2 Alternative functions are listed lowest priority first. For example, GPIO is the lowest priority alternative function of the

PTA0 pin; ACMP+ is the highest priority alternative function of the PTA0 pin.

VDD

——

Power

VSS

—

Ground

PTA0

I/O

SWC

PTA0

KBIP0

ACMP+

General-purpose input/output (GPIO)

Keyboard interrupt (stop/wait wakeup only)

Analog comparator input

PTA1

I/O

SWC

PTA1

KBIP1

ACMP-

General-purpose input/output (GPIO)

Keyboard interrupt (stop/wait wakeup only)

Analog comparator input

PTA2

SWC4

PTA2

KBIP2

TCLK

RESET

VPP

General-purpose input

Keyboard interrupt (stop/wait wakeup only)

Modulo timer clock source

Reset

VPP

PTA3

I/O3

3 Output-only when configured as PTA3 function.

—4

4 When PTA2 or PTA3 is configured as RESET or BKGD/MS, respectively, pullup is enabled. When V

PP is attached,

pullup/pulldown is disabled automatically.

PTA3

ACMPO

BKGD

General-purpose output

Analog comparator output

Background debug data

Mode select

PTA45

5 This pin is not available in 6-pin package. Enabling either the pullup or pulldown device is recommended to prevent extra

current leakage from the floating input pin.

I/O

SWC

PTA4

KBIP4

General-purpose input/output (GPIO)

Keyboard interrupt (stop/wait wakeup only)

PTA55

I/O

SWC

PTA5

KBIP5

General-purpose input/output (GPIO)

Keyboard interrupt (stop/wait wakeup only)

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