4-47

Features

• Cascadable Up to 4 Units for 32-Bit by 32-Bit Multiply

or 64

• 8-Bit by 8-Bit Multiply or 16

5V or 2.8

µs at 10V

• Direct Interface to CDP1800-Series Microprocessors

• Easy Interface to Other 8-Bit Microprocessors

• Significantly Increases Throughput of Microprocessor

Used for Arithmetic Calculations

Description

The CDP1855 and CDP1855C are CMOS 8-bit multi-

ply/divide units which can be used to greatly increase the

capabilities of 8-bit microprocessors. They perform multiply

and divide operations on unsigned, binary operators. In

general, microprocessors do not contain multiply or divide

instructions and even efficiently coded multiply or divide

subroutines require considerable memory and execution

time. These multiply/divide units directly interface to the

CDP1800-series microprocessors via the N-lines and can

easily be configured to fit in either the memory or I/O space

of other 8-bit microprocessors.

The multiple/divide unit is based on a method of multiplying

by add and shift right operations and dividing by subtract and

shift left operations. The device is structured to permit cas-

cading identical units to handle operands up to 32 bits.

The CDP1855 and CDP1855C are functionally identical.

They differ in that the CDP1855 has a recommended

operating voltage range of 4V to 10.5V, and the CDP1855C,

a recommended operating voltage range of 4V to 6.5V.

The CDP1855 and CDP1855C types are supplied in a 28

lead hermetic dual-in-line ceramic package (D suffix) and in

a 28 lead dual-in-line plastic package (E suffix). The

CDP1855C is also available in chip form (H suffix).

Ordering Information

PACKAGE TEMP. RANGE

5V

10V

PKG.

NO.

PDIP

CDP1855E E28.6

Burn-In

CDP1855CEX

-

E28.6

SBDIP

Burn-In

CDP1855CDX

-

D28.6

Pinout

28 LEAD DIP

TOP VIEW

Circuit Configuration

CE

CLEAR

CTL

C.O./O.F.

SHIFT

CLK

STB

RD/WE

RA2

RA1

RA0

CN1

CI

BUS 6

BUS 4

BUS 3

BUS 2

BUS 1

BUS 0

CN0

BUS 7

BUS 5

28

27

26

25

24

23

22

21

20

19

18

17

16

15

1

2

3

4

5

6

7

8

9

10

11

12

13

14

CLEAR

XTAL

N0

N1

N2

TPB

MRD

CDP1802

BUS

EF

CLEAR

CLK

RA0

RA1

RA2

STB

RD/WE

CDP1855

BUS

C0

CTL

CE

C1

CN0

CN1

+V

FIGURE 1. MDU ADDRESSED AS I/O DEVICE

March 1997

CDP1855,

CDP1855C

8-Bit Programmable

Multiply/Divide Unit

File Number

1053.2

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

http://www.intersil.com or 407-727-9207