A8251 Datasheet, PDF (1/21 Pages) Altera Corporation – Programmable Communications Interface

June 1997, ver. 2
Features
General
Description
a8251
®
Programmable Communications
Interface
Data Sheet
s a8251 MegaCore function that provides an interface between a
microprocessor and a serial communication channel
s Optimized for FLEX^® architecture
s Programmable word length, stop bits, and parity
s Offers divide-by-1, -16, or -64 mode
s Supports synchronous and asynchronous operation
s Uses approximately 528 FLEX logic elements (LEs)
s Includes:
– Error detection
– False start bit detection
– Automatic break detection
– Internal and external sync character detection
s Functionally based on the Intel M8251A device, except as noted in the
“Variations & Clarifications” on page 44
The a8251 MegaCore function provides an interface between a
microprocessor and a serial communications channel. The a8251 receives
and transmits data in a variety of configurations including 7- or 8-bit data
words, with odd, even, or no parity, and 1 or 2 stop bits. The transmitter
and receiver can be designed for synchronous or asynchronous operation.
See Figure 1.
Figure 1. a8251 Symbol
A8251
CLK
CnD
DIN[7..0]
EXTSYNCD
nCS
nCTS
nDSR
nRD
nRXC
nTXC
nWR
RESET
RXD
DOUT[7..0]
nDTR
nEN
nRTS
RXRDY
SYN_BRK
TXD
TXEMPTY
TXRDY
Altera Corporation
25
A-DS-A8251-2