© 2012 Rochester Electronics, LLC. All Rights Reserved 12192012
8251A
hronous Receiver/Transmitter (USART)
The 8251A is the industry standard Universal Synchronous/Async
such as MCS-48, 80, 85, and iAPX 86, 88.
designed for data communications with microprocessor families
the CPU to operate using virtually any serial
The 8251A is used as a peripheral device and is programmed by
c”). The USART accepts data characters
data transmission technique presently in use (including IBM “bi-syn
uous serial data stream for transmission.
from the CPU in parallel format and then converts them into a contin
into parallel data characters for the CPU.
Simultaneously, it can receive serial data streams and convert them
ter for transmission or whenever it has
The USART will signal the CPU whenever it can accept a new charac
status of the USART at any time. These
received a character for the CPU. The CPU can read the complete
ET, TxEMPTY. The chip is fabricated using
include data transmission errors and control signals such as SYND
Intel’s high performance HMOS technology.
* For complete Rochester ordering guide, please refer to page 2 *
Rochester Electronics guarantees performance of its semiconductor products to the original OEM specifications. “Typical” values are for reference purposes
only. Certain minimum or maximum ratings may be based on product characterization, design, simulation, or sample testing. Rochester Electronics reserves
the right to make changes without further notice to any specification herein.
Specification Number 8251A-CI (I) REV A
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