INTEGRATED CIRCUITS SCC2681 Dual asynchronous receiver/transmitter (DUART) Product data 2004 Apr 06 Philips Semiconductors Product data Dual asynchronous receiver/transmitter (DUART) SCC2681 DESCRIPTION 16-bit programmable Counter/Timer The Philips Semiconductors SCC2681 Dual Universal Non-standard rates to 115.2 kb Asynchronous Receiver/Transmitter (DUART) is a single-chip One user-defined rate derived from programmable MOS-LSI communications device that provides two independent timer/counter full-duplex asynchronous receiver/transmitter channels in a single External 1 or 16 clock package. It interfaces directly with microprocessors and may be used in a polled or interrupt driven system. It is manufactured in a Parity, framing, and overrun error detection CMOS process. False start bit detection The operating mode and data format of each channel can be Line break detection and generation programmed independently. Additionally, each receiver and transmitter can select its operating speed as one of eighteen fixed Programmable channel mode baud rates, a 16 clock derived from a programmable counter/timer, Normal (full-duplex) or an external 1 or 16 clock. The baud rate generator and Automatic echo counter/timer can operate directly from a crystal or from external Local loopback clock inputs. The ability to independently program the operating Remote loopback speed of the receiver and transmitter make the DUART particularly attractive for dual-speed channel applications such as clustered Multi-function programmable 16-bit counter/timer terminal systems. Multi-function 7-bit input port Each receiver is quadruply buffered to minimize the potential of Can serve as clock or control inputs receiver over-run or to reduce interrupt overhead in interrupt driven Change of state detection on four inputs systems. In addition, a flow control capability is provided to disable a remote DUART transmitter when the buffer of the receiving device is 100 k typical pull-up resistor full. Multi-function 8-bit output port Also provided on the SCC2681 are a multipurpose 7-bit input port Individual bit set/reset capability and a multipurpose 8-bit output port. These can be used as general Outputs can be programmed to be status/interrupt signals purpose I/O ports or can be assigned specific functions (such as DMA signals clock inputs or status/interrupt outputs) under program control. Auto 485 turn-around The SCC2681 is available in three package versions: 40-pin and Versatile interrupt system 28-pin DIPs (both 0.6 wide) and a 44-pin PLCC. Single interrupt output with eight maskable interrupting conditions FEATURES Output port can be configured to provide a total of up to six Dual full-duplex asynchronous receiver/transmitter separate wire-ORable interrupt outputs Quadruple buffered receiver data registers Maximum data transfer: 1 1 MB/sec 16 125 kB/sec Programmable data format Automatic wake-up mode for multidrop applications 5 to 8 data bits plus parity Start-end break interrupt/status Odd, even, no parity or force parity Detects break which originates in the middle of a character 1, 1.5 or 2 stop bits programmable in 1/16-bit increments On-chip crystal oscillator Programmable baud rate for each receiver and transmitter selectable from: Single +5 V power supply 22 fixed rates: 50 to 115.2 k baud Commercial and industrial temperature ranges available DIP and PLCC packages ORDERING INFORMATION Type number Package Name Description Version Commercial V = +5 V 5% T = 0 C to +70 C CC amb SCC2681AC1A44 PLCC44 plastic leaded chip carrier 44 leads SOT187-2 SCC2681AC1N28 DIP28 plastic dual in-line package 28 leads (600 mil) SOT117-1 SCC2681AC1N40 DIP40 plastic dual in-line package 40 leads (600 mil) SOT129-1 Industrial V = +5 V 10% T = 40 C to +85 C CC amb SCC2681AE1A44 PLCC44 plastic leaded chip carrier 44 leads SOT187-2 SCC2681AE1N28 DIP28 plastic dual in-line package 28 leads (600 mil) SOT117-1 SCC2681AE1N40 DIP40 plastic dual in-line package 40 leads (600 mil) SOT129-1 2004 Apr 06 2