• 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 5.6µs at
5V or 2.8µs at 10V
• Direct Interface to CDP1800-Series Microprocessors
• Easy Interface to Other 8-Bit Microprocessors
• Signiﬁcantly Increases Throughput of Microprocessor
Used for Arithmetic Calculations
PACKAGE TEMP. RANGE
-40oC to +85oC CDP1855CE
CDP1855CEX - E28.6
-40oC to +85oC CDP1855CD CDP1855D D28.6
CDP1855CDX - D28.6
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).
28 LEAD DIP
22 BUS 7
21 BUS 6
20 BUS 5
19 BUS 4
18 BUS 3
17 BUS 2
16 BUS 1
15 BUS 0
FIGURE 1. MDU ADDRESSED AS I/O DEVICE
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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File Number 1053.2