34C60 datasheet(9/58 Pages) SMSC

9 / 58 page

SMSC DS – PPC34C60

Page 9

Rev. 06/01/2001

ADVANCED INFORMATION

DESCRIPTION OF PIN FUNCTIONS

PIN NO.

NAME

SYMBOL

BUFFER

TYPE

DESCRIPTION

Terminal Count

This active high output is asserted with

the last DMA data transfer to indicate to

the System that the DMA data transfer is

complete. TC is asserted in conjunction

with DACK.

DMA Request

DREQ

I, PD

The remote system indicates that it is

ready to perform DMA transfers by

driving this line high.

This signal is

asserted as long as the System is ready

to receive or send data and is deasserted

on the last byte of the data transfer.

MISCELLANEOUS

nWatchdog Enable nWDOGEN

I, PU

Pulling

this

line

low enables

the

watchdog. The watchdog will generate

four beeps on the piezo driver if there are

no transitions on the host port lines for a

minute.

This

circuitry

can

also

automatically power down the system

when the watchdog "barks". This feature

requires software to tickle the port every

30 seconds.

nReset Chip

nRESET

I, PU

Pulling this line low for two SYSCLKs will

reset the PPC34C60 to its initial state.

This will reset all internal registers to their

default values.

nLow

Battery

Indicator

nLBAT

I, PU

A low level on this input line signals that

the battery power is low and the

PPC34C60 will generate low battery

tones.

It is the responsibility of the

remote system to monitor battery power

and generate this input signal.

82,83,

37,36

General

Purpose

Inputs [0:3]

IN[0:3]

I, PU

The host may obtain the level at these

pins by reading the Internal Input

Piezo Crystal Drive PIEZO

O24

This high current output can be directly

hooked up to a piezo speaker to provide

audio tones.

44,43, 42 nStrobes[0:2]

(special function)

nST[0:2]

These pins are individually configured as

general purpose outputs or as strobe

outputs as programmed in the Output

Configuration Register. ST2 may also be

programmed as the Auto-Power pin.

84-87

nChip Selects[0:3]

(special function)

nCS[0:3]

These pins are individually configured as

general purpose outputs or as chip select

outputs as programmed in the Output

Configuration Register.

Oscillator Input

Oscillator Output

YIN

YOUT

A parallel resonant crystal or RC network

may be placed across YIN and YOUT.

This nominal 32KHz clock (32.768KHz) is

used by the internal piezo driver and

watchdog timer.

34C60 Datasheet(PDF) 9 Page - SMSC Corporation

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