INTEGRATED CIRCUITS SCC68681 Dual asynchronous receiver/transmitter (DUART) Product data 2004 Apr 06 Philips Semiconductors Product data Dual asynchronous receiver/transmitter (DUART) SCC68681 DESCRIPTION 16-bit programmable Counter/Timer The Philips Semiconductors SCC68681 Dual Universal Parity, framing, and overrun error detection Asynchronous Receiver/Transmitter (DUART) is a single-chip MOS-LSI communications device that provides two independent False start bit detection full-duplex asynchronous receiver/transmitter channels in a single Line break detection and generation package. It is compatible with other S68000 family devices, and can also interface easily with other microprocessors. The DUART can be Programmable channel mode used in polled or interrupt driven systems. It is manufactured in a Normal (full-duplex) CMOS process. Automatic echo The operating mode and data format of each channel can be Local loopback programmed independently. Additionally, each receiver and Remote loopback transmitter can select its operating speed as one of eighteen fixed baud rates, a 16 clock derived from a programmable counter/timer, Multi-function programmable 16-bit counter/timer or an external 1 or 16 clock. The baud rate generator and Multi-function 6-bit input port counter/timer can operate directly from a crystal or from external clock inputs. The ability to independently program the operating Can serve as clock or control inputs speed of the receiver and transmitter make the DUART particularly Change-of-state detection on four inputs attractive for dual-speed channel applications such as clustered 100 k typical pull-up resistors terminal systems. Multi-function 8-bit output port Each receiver is quadruply buffered to minimize the potential of Individual bit set/reset capability receiver overrun or to reduce interrupt overhead in interrupt driven Outputs can be programmed to be status/interrupt/DMA signals systems. In addition, a flow control capability is provided to disable a remote DUART transmitter when the buffer of the receiving device is Auto 485 turn-around full. Versatile interrupt system Also provided on the SCC68681 are a multipurpose 6-bit input port Single interrupt output with eight maskable interrupting and a multipurpose 8-bit output port. These can be used as general conditions purpose I/O ports or can be assigned specific functions (such as Interrupt vector output on interrupt acknowledge clock inputs or status/interrupt outputs) under program control. Output port can be configured to provide a total of up to six separate wire-ORable interrupt outputs FEATURES Maximum data transfer rates: 1 = 1 MB/sec 16 = 125 kB/sec S68000 bus compatible Automatic wake-up mode for multidrop applications Dual full-duplex asynchronous receiver/transmitter Start-end break interrupt/status Quadruple buffered receiver data registers Detects break which originates in the middle of a character Programmable data format On-chip crystal oscillator 5 to 8 data bits plus parity Odd, even, no parity or force parity Single +5 V power supply 1, 1.5 or 2 stop bits programmable in 1/16-bit increments Commercial and industrial temperature ranges available Programmable baud rate for each receiver and transmitter DIP and PLCC packages selectable from: 22 fixed rates: 50 to 115.2 kbaud Non-standard rates to 115.2 kb Non-standard user-defined rate derived from programmable counter/timer External 1 or 16 clock ORDERING INFORMATION Type number Package Name Description Version Commercial V = +5 V 5% T = 0 C to +70 C CC amb SCC68681C1A44 PLCC44 plastic leaded chip carrier 44 leads SOT187-2 SCC68681C1N40 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 SCC68681E1A44 PLCC44 plastic leaded chip carrier 44 leads SOT187-2 SCC68681E1N40 DIP40 plastic dual in-line package 40 leads (600 mil) SOT129-1 2004 Apr 06 2