
4-47
Features
Cascadable Up to 4 Units for 32-Bit by 32-Bit Multiply
or 64
32-Bit Divide
8-Bit by 8-Bit Multiply or 16
÷
8-Bit Divide in 5.6
μ
s at
5V or 2.8
μ
s 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
-40
o
C to +85
o
C CDP1855CE
CDP1855E E28.6
Burn-In
CDP1855CEX
-
E28.6
SBDIP
-40
o
C to +85
o
C CDP1855CD CDP1855D D28.6
Burn-In
CDP1855CDX
-
D28.6
Pinout
28 LEAD DIP
TOP VIEW
Circuit Configuration
CE
CLEAR
CTL
C.O./O.F.
Y
L
Z
L
SHIFT
CLK
STB
RD/WE
RA2
RA1
RA0
V
SS
V
DD
CN0
CN1
CI
Y
R
Z
R
BUS 7
BUS 6
BUS 4
BUS 3
BUS 2
BUS 1
BUS 0
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
Y
L
Z
R
CTL
Y
R
Z
L
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
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Copyright
Intersil Corporation 1999