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