INTEGRATED CIRCUITS
SCC2691
Universal asynchronous
receiver/transmitter (UART)
Product data sheet 2006 Aug 04
Supersedes data of 1998 Sep 04
Philips Semiconductors Product data sheet
Universal asynchronous receiver/transmitter (UART) SCC2691
DESCRIPTION PIN CONFIGURATIONS
The Philips Semiconductors SCC2691 Universal Asynchronous
Receiver/Transmitter (UART) is a single-chip CMOS-LSI
RDN 1 24 V
CC
communications device that provides a full-duplex asynchronous
2 23
RxD WRN
receiver/transmitter. It is fabricated with Philips Semiconductors
CMOS technology which combines the benefits of high density and
3 22
TxD D0
low power consumption.
MPO 4 21 D1
The operating speed of the receiver and transmitter can be selected
5 20
MPI D2
independently as one of 18 fixed baud rates, a 16X clock derived
N24
6 19
from a programmable counter/timer, or an external 1X or 16X clock. A2 D3
AND
D24
The baud rate generator and counter/timer can operate directly from
A1 7 18 D4
PACKAGES
a crystal or from external clock inputs. The ability to independently
8 17
A0 D5
program the operating speed of the receiver and transmitter make
the UART particularly attractive for dual-speed channel applications
9 16
X1/CLK D6
such as clustered terminal systems.
X2 10 15 D7
The receiver is quadruple buffered to minimize the potential of
11 14
RESET CEN
receiver overrun or to reduce interrupt overhead in interrupt driven
13
systems. In addition, a handshaking capability is provided to disable GND 12 INTRN
a remote UART transmitter when the receiver buffer is full.
The UART provides a power-down mode in which the oscillator is
41 26
frozen but the register contents are stored. This results in reduced
power consumption on the order of several magnitudes.
5 25
The UART is fully TTL compatible and operates from a single +5V
A28
power supply.
PACKAGE
11 19
FEATURES
12 18
Full-duplex asynchronous receiver/transmitter
Pin Symbol Pin Symbol
Quadruple buffered receiver data register
1 V 15 GND
CC
2 RDN 16 INTRN
Programmable data format:
3 RxD 17 CEN
4 TxD 18 D7
5 to 8 data bits plus parity
5 MPO 19 D6
6 MPI 20 D5
Odd, even, no parity or force parity
7 NC 21 D4
8 NC 22 D3
1, 1.5 or 2 stop bits programmable in 1/16-bit increments
9 A2 23 NC
10 A1 24 D2
16-bit programmable Counter/Timer
11 A0 25 D1
12 X1/CLK 26 NC
Baud rate for the receiver and transmitter selectable from:
13 X2 27 D0
14 RESET 28 WRN
22 fixed rates: 50 to 115.2K baud SD00122
Non-standard rates to 115.2 kb
Figure 1. Pin Configurations
Non-standard user-defined rate derived from programmable
timer/ counter
Single interrupt output with seven maskable interrupting
External 1X or 16X clock
conditions
Parity, framing, and overrun detection
On-chip crystal oscillator
False start bit detection
Low power mode
Line break detection and generation
TTL compatible
Programmable channel mode
Single +5V power supply
Normal (full-duplex)
Commercial (0C to +70C) and industrial (-40C to +85C)
Automatic echo
temperature versions available
Local loopback
SOL, PLCC and 300 mil wide DIP packages available
Remote Loopback
Multi-function programmable 16-bit counter/timer
2006 Aug 04 2