CDP1878C View Datasheet(PDF) - Intersil

Part Name

Description

Manufacturer

CDP1878C

CMOS Dual Counter-Timer

Intersil 

Functional Diagram

RESET

RD

TPB/WR

IO/MEM

TPA

CS

A2

A1

A0

VDD

VSS

8-BIT

EXTERNAL

BUS

I-O

CONTROL

AND

LOGIC

DATA

BUS

DRIVERS

CDP1878C

JAM

REGISTER A

COUNTER A

HOLDING

REGISTER A

JAM

REGISTER B

COUNTER B

HOLDING

REGISTER B

CONTROL REGISTER A

AND MODE CONTROL

GATE A

TAO

TAO

CLOCK A

INT AND

STATUS REGISTER

INT

CONTROL REGISTER B

AND MODE CONTROL

GATE B

TBO

TBO

CLOCK B

FUNCTIONAL DEFINITIONS FOR CDP1878C TERMINALS

TERMINAL

USAGE

VDD - VSS

DB0-DB7

Power

Data to and from device

TPB/WR, RD Directional Control Signals

A0, A1, A2 Addresses that select counters or registers

TACL, TBCL Clocks used to decrement counters

TAG, TBG Gate inputs that control counters

TERMINAL

TAO, TAO

TBO, TBO

TPA

CS

INT

RESET

IO/MEM

USAGE

Complemented outputs of Timer A

Complemented outputs of Timer B

Used with CDP1800-series processors, tied high

otherwise

Active high input that enables device

Low when counter is “0”

When active, TAO, TBO are low, TAO, TBO are

high. Interrupt status register is cleared.

Tied high in CDP1800 input/output mode, other-

wise tied low

4-93

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