CDP1851,
CDP1851C
TM
CMOS Programmable I/O Interface
March 1997
Features
Description
• 20 Programmable I/O Lines
THE CDP1851 and CDP1851C are CMOS programmable twoport I/Os designed for use as general-purpose I/O devices.
They are directly compatible with CDP1800-series microprocessors functioning at maximum clock frequency. Each port
can be programmed in either byte-I/O or bit-programmable
modes for interfacing with peripheral devices such as printers
and keyboards.
• Programmable for Operation in Four Modes:
- Input
- Output
- Bidirectional
- Bit-programmable
• Operates in Either I/O or Memory Space
Ordering Information
PACKAGE TEMP. RANGE
5V
-40oC to +85oC CDP1851CE
PDIP
Burn-In
SBDIP
CDP1851E
CDP1851CEX
E40.6
-
E40.6
-
-40oC to +85oC CDP1851CD
Burn-In
PKG.
NO.
10V
D40.6
CDP1851CDX CDP1851DX D40.6
Both ports A and B can be separately programmed to be 8-bit
input or output ports with handshaking control lines, RDY and
STROBE. Only port A can be programmed to be a bidirectional
port. This configuration provides a means for communicating
with a peripheral device or microprocessor system on a single
8-bit bus for both transmitting and receiving data. Handshaking
signals are provided to maintain proper bus access control.
Port A handshaking lines are used for input control and port B
handshaking lines are used for output; therefore port B must be
in the bit-programmable mode where handshaking is not used.
Ports A and B can be separately bit programmed so that each
individual line can be designated as an input or output line. The
handshaking lines may also be individually programmed as
input or output when port A is not in bidirectional mode.
The CDP1851 has a supply-voltage range of 4V to 10.5V, and
the CDP1851C has a range of 4V to 6.5V. Both types are supplied in 40-lead dual-in-line plastic (E suffix) or hermetic
ceramic (D suffix) packages. The CDP1851C is also available
in chip form (H suffix).
CDP1851 Programming Modes
Pinout
CDP1851, CDP1851C
(PDIP, SBDIP)
TOP VIEW
CLOCK 1
40 VDD
CS 2
39 RD/WE
RA0 3
38 WR/RE
RA1 4
MODE
37 TPB
BUS0 5
BUS2 7
36 A RDY
35 A
STROBE
34 A0
BUS3 8
33 A1
BUS4 9
32 A2
BUS5 10
29 A5
CLEAR 13
28 A6
A INT 14
27 A7
B INT 15
READY, STROBE
Accept Input Data
READY, STROBE
Output
Output Data
READY, STROBE
Output Data
READY, STROBE
Bidirectional
(Port A Only)
Transfer Input/Output Data
Input Handshaking
for Port A
Must be Previously Set to Bit-Programmable Mode
Output Handshaking
for Port A
Bit-Programmable
Programmed Individually as Inputs or Outputs
Programmed Individually as Inputs or Outputs
Programmed Individually as Inputs
or Outputs
Programmed Individually as Inputs or Outputs
22 B3
VSS 20
Accept Input
Data
25 B6
B1 19
Input
26 B7
B RDY 16
B 17
STROBE
B0 18
(2)
PORT B
HANDSHAKING
PINS
(8)
PORT B
DATA PINS
30 A4
BUS7 12
(2)
PORT A
HANDSHAKING
PINS
31 A3
BUS6 11
(8)
PORT A
DATA PINS
21 B2
BUS1 6
24 B5
23 B4
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a trademark of Intersil Americas Inc.
1
Copyright © Intersil Americas Inc. 2002. All Rights Reserved
File Number
1056.2
