Programmable Universal Asynchronous
• Two Operating Modes
- Mode 0 - Functionally Compatible with Industry
Types Such as the TR1602A and CDP6402
- Mode 1 - Interfaces Directly with CDP1800-Series
Microprocessors without Additional Components
• Full or Half Duplex Operation
• Parity, Framing and Overrun Error Detection
• Baud Rate
- DC to 200K Bits/s at VDD . . . . . . . . . . . . . . . . . . . . 5V
- DC to 400K Bits/s at VDD . . . . . . . . . . . . . . . . . . . . 10V
• Fully Programmable with Externally Selectable Word
Length (5-8 Bits), Parity Inhibit, Even/Odd Parity, and
1, 1-1/2, or 2 Stop Bits
• False Start Bit Detection
The CDP1854A and CDP1854AC are silicon-gate CMOS
Universal Asynchronous Receiver/Transmitter (UART) cir-
cuits. They are designed to provide the necessary formatting
and control for interfacing between serial and parallel data.
For example, these UARTs can be used to interface between
a peripheral or terminal with serial I/O ports and the 8-bit
CDP1800-series microprocessor parallel data bus system.
The CDP1854A is capable of full duplex operation, i.e.,
simultaneous conversion of serial input data to parallel out-
put data and parallel input data to serial output data.
The CDP1854A UART can be programmed to operate in one
of two modes by using the mode control input. When the
input is high (MODE = 1), the CDP1854A is directly compati-
ble with the CDP1800-series microprocessor system without
additional interface circuitry. When the mode input is low
(MODE = 0), the device is functionally compatible with indus-
try standard UART’s such as the TR1602A and CDP6402. It
is also pin compatible with these types, except that pin 2 is
used for the mode control input.
-40oC to +85oC CDP1854ACE
-40oC to +85oC CDP1854ACQ
-40oC to +85oC CDP1854ACD
The CDP1854A and the CDP1854AC are functionally identi-
cal. The CDP1854A has a recommended operating voltage
range of 4V to 10.5V, and the CDP1854AC has a recom-
mended operating voltage range of 4V to 6.5V.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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