R65C51 Datasheet, PDF (1/19 Pages) List of Unclassifed Manufacturers – ASYNCHRONOUS COMMUNICATIONS INTERFACE ADAPTER

R65C51
ASYNCHRONOUS COMMUNICATIONS
DESCRIPTION
PRELiMlNARY
FEATURES
The Rockwell CMOS R65C51 Asynchronous Communications
Interface Adapter (ACIA) provides an easily implemented, pro-
gram controlled interface between 8-bit microprocessor-based
systems and serial communication data sets and modems.
The ACIA has an internal baud rate generator. This feature elim-
inates the need for multiple component support circuits, a crystal
being the only other part required. The Transmitter baud rate
can be selected under program control to be either 1 of 15 dif-
ferent rates from 50 to 19,200 baud, or at l/16 times an external
clock rate. The Receiver baud rate may be selected under pro-
gram control to be either the Transmitter rate, or at l/16 times
the external clock rate. The ACIA has programmable word
lengths of 5, 6, 7, or 8 bits; even, odd, or no parity; 1, 1'12, or
2 stop bits.
The ACIA is designed for maximum programmed control from
the microprocessor (MPU), to simplify hardware implementa-
tion. Three separate registers permit the MPU to easily select
the R65C51’s operating modes and’ data checking parameters
and determine operational status.
The Command Register controls parity, receiver echo mode,
transmitter interrupt control, the state of the RTS line, receiver
interrupt control, and the state of the DTR line.
Low power CMOS N-well silicon gate technology
Direct replacement for NMOS R6551 ACIA
Full duplex operation with buffered receiver and transmitter
Data set/modem control functions
Internal baud rate generator with 15 programmable bau
rates (50 to 19,200)
. Program-selectable internally or’externally controlled receive
rate
. Programmable word lengths, number of stop bits, and pant
bit generation and detection
Programmable interrupt control
Program reset
Program-selectable serial echo mode
Two chip selects
1 or 2 MI-Q operation
5.0 Vdc t 5% supply requirements
28-pin plastic or ceramic DIP
Full TTL compatibility
Compatible with. R6500, R6500/’ and R65COO micro-
processors
The Control Register controls the number of stop bits, word
length, receiver clock source, and baud rate.
--
The Status Register indicates the states of the IRQ, DSR, and
DCD lines. Transmitter and Receiver Data Registers, and
Overrun, Framing, and Parity Error conditions,
The Transmitter and Receiver Data Registers are used for tem-
porary data storage by the ACIA Transmit and Receiver circuits.
ORDERING INFORMATION
Part No.: R65C51
-
Temperature Range (TL to TH):
Blank = 0% to +70°C
E= -40% to +85%
Frequency Range:
1 = 1 MHz
2 = 2 MHz
Package:
C = Ceramic
P = Plastic
Document No. 29651 N60
2-296
Figure 1. R65C51 AClA Pin Configuration
Product Description Order No. 2157
Rev. 3, October 1984