
1
TM
Features
Static Silicon-Gate CMOS Circuitry
Parallel 8-Bit Data Register and Buffer
Handshaking Via Service Request Flip-Flop
Low Quiescent and Operating Power
Interfaces Directly with CDP1800-Series Microproces-
sors
Single Voltage Supply
Full Military Temperature Range
(-55
o
C to +125
o
C)
Pinout
CDP1852/3, CDP1852C/3 (SBDIP)
TOP VIEW
Description
The CDP1852/3 and CDP1852C/3 are parallel, 8-bit, mode-
programmable input/output ports. They are compatible and
will interface directly with CDP1800-Series microprocessors.
They are also useful as 8-bit address latches when used
with the CDP1800 multiplexed address bus and as I/O ports
in general-purpose applications.
The mode control is used to program the device as an input
port (mode = 0) or as an output port (mode = 1). The SR/SR
output can be used as a signal to indicate when data is
ready to be transferred. In the input mode, a peripheral
device can strobe data into the CDP1852/3, and micropro-
cessor can read that data by device selection. In the output
mode, a microprocessor strobes data into the CDP1852/3,
and handshaking is established with a peripheral device
when the CDP1852/3 is deselected.
In the input mode, data at the data-in terminals (DI0-DI7) is
strobed into the port’s 8-bit register by a high (1) level on the
clock line. The negative high-to-low transition of the clock
latches the data in the register and sets the service request
output low (SR/SR = 0). When CS1/CS1 and CS2 are high
(CS1/CS1 and CS2 = 1), the three-state output drivers are
enabled and data in the 8-bit register appear at the data-out
terminals (DO0-DO7). When either CS1/CS1 or CS2 goes low
(CS1/CS1 or CS2 = 0), the data-out terminals are tristated
and the service request output returns high (SR/SR =1).
In the output mode, the output drivers are enabled at all
times. Data at the data-in terminals (DI0-DI7) is strobed into
the 8-bit register when CS1/CS1 is low (CS1/CS1 = 0) and
CS2 and the clock are high (1), and are present at the data-
out terminals (DO0-DO7). The negative high-to-low transi-
tion of the clock latches the data in the register. The SR/SR
output goes high (SR/SR = 1) when the device is deselected
(CS1/CS1 = 1 or CS2 = 0) and returns low (SR/SR = 0) on the
following trailing edge of the clock.
A CLEAR control is provided for resetting the port’s register
(DO0-DO7 = 0) and service request flip-flop (input
mode: SR/SR = 1 and output mode: SR/SR = 0).
The CDP1852/3 is functionally identical to the CDP1852C/3.
The CDP1852/3 has a recommended operating voltage
range of 4V to 10.5V, and the CDP1852C/3 has a recom-
mended operating voltage range of 4V to 6.5V.
The CDP1852/3 and CDP1852C/3 are supplied in 24-lead,
dual-in-line side-brazed ceramic packages (D suffix).
Ordering Information
PACK-
AGE
TEMP.
RANGE
-55
o
C to +125
o
C CDP1852CD3 CDP1852D3 D24.6
5V
10V
PKG.
NO
SBDIP
1
2
3
4
5
6
7
8
9
10
11
12
CSI/CSI
MODE
DI0
DO0
DI1
DO1
DI2
DO2
DI3
DO3
CLOCK
V
SS
16
17
18
19
20
21
22
23
24
15
14
13
V
DD
SR/SR
DI7
DO7
DI6
DO6
DO5
DO4
CLEAR
CS2
DI5
DI4
March 1997
File Number
1694.2
CDP1852/3,
CDP1852C/3
High-Reliability Byte-Wide Input/Output Port
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143
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