IA8251 Datasheet, PDF (2/4 Pages) InnovASIC, Inc – Programmable Communication Interface

IA8251
Page 2 of 4
Advanced Information Sheet
Programmable Communication Interface
The IA8251 provides an interface between a microprocessor and a serial communications channel.
The IA8251 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.
A block diagram is shown in Figure 1.
Functional Block Diagram
Figure 1
INTERNAL DATA
BUS
D7:D0
DATA BUS
BUFFER
GROUP A
PORT A
(8)
TXD
RESET
CLK
CD_n
RD_n
WR_n
CS_n
DSR_n
DTR_n
CTS_n
RTS_n
READ/WRITE
CONTROL
LOGIC
MODEM
CONTROL
GROUP A
PORT C
UPPER (4)
TXRDY
TXEMPTY
TXC_n
GROUP B
PORT C
LOWER
(4)
RXD
GROUP B
PORT B
(8)
RXRDY
RXC_n
SYNDET_BD
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