SC28L92

•Member of IMPACT family: 3.3 to 5.0 volt , 40°C to +85°C and68K for 80xxx bus interface for all devices.
• Dual full-duplex independent asynchronous receiver/transmitters
• 16 character FIFOs for each receiver and transmitter
• Pin programming selects 68K or 80xxx bus interface
• Programmable data format 5 to 8 data bits plus parity Odd, even, no parity or force parity - 1, 1.5 or 2 stop bits programmable in 1/16-bit increments
• 16-bit programmable Counter/Timer
• Programmable baud rate for each receiver and transmitterselectable from: 28 fixed rates: 50 to 230.4k baud Other baud rates to MHz at 16XProgrammable user-defined rates derived from a programmablecounter/timer External 1X or 16X clock
• Parity, framing, and overrun error detection
• False start bit detection
• Line break detection and generation
• Programmable channel mode Normal (full-duplex) Automatic echo Local loop back Remote loop back Multi-drop mode (also called 'wake-up' or '9-bit')
•Multi-function 7-bit input port (includes IACKN) Can serve as clock or control inputs Change of state detection on four inputs Inputs have typically >100k pull-up resistors Change of state detectors for modem control
•Multi-function 8-bit output port Individual bit set/reset capability Outputs can be programmed to be status/interrupt signals FIFO status for DMA interface
• Versatile interrupt system Single interrupt output with eight maskable interruptingconditions Output port can be configured to provide a total of up to sixseparate interrupt outputs that may be wire ORed. Each FIFO can be programmed for four different interrupt levels Watch dog timer for each receiver
•Maximum data transfer rates:1X 1Mb/sec, 16X 1Mb/sec
• Automatic wake-up mode for multi-drop applications
• Start-end break interrupt/status
• Detects break which originates in the middle of a character
• On-chip crystal oscillator
• Power down mode
• Receiver time-out mode
• Single +3.3V or +5V power supply
• Powers up to emulate SC26C92

The SC28L92 is a pin and function replacement for the SCC2692and SC26C92 operating at 3.3 or 5 volts supply with added featuresand deeper FIFOs. Its configuration on power up is that of theSC26C92. Its differences from the 2692 are: 16 character receiver, 16character transmit FIFOs, watch dog timer for each receiver, moderegister 0 is added, extended baud rate and overall faster speeds,programmable receiver and transmitter interrupts. (Neither theSC26C92 nor the SCC2692 is being discontinued.)

Pin programming will allow the device to operate with either theMotorola or Intel bus interface. The bit 3 of the MR0a register allowsthe device to operate in an 8 byte FIFO mode if strict compliancewith the SC26C92 FIFO structure is required.

The Philips Semiconductors SC28L92 Dual Universal AsynchronousReceiver/Transmitter (DUART) is a single-chip CMOS-LSIcommunications device that provides two full-duplex asynchronousreceiver/transmitter channels in a single package. It interfacesdirectly with microprocessors and may be used in a polled orinterrupt driven system with modem and DMA interface.

The operating mode and data format of each channel can beprogrammed independently. Additionally, each receiver andtransmitter can select its operating speed as one of 28 fixed baudrates; a 16X clock derived from a programmable counter/timer, or anexternal 1X or 16X clock. The baud rate generator and counter/timercan operate directly from a crystal or from external clock inputs. Theability to independently program the operating speed of the receiverand transmitter make the DUART particularly attractive fordual-speed channel applications such as clustered terminalsystems.

Each receiver and transmitter is buffered by 8 or 16 character FIFOsto minimize the potential of receiver overrun, transmitter underrunand to reduce interrupt overhead in interrupt driven systems. Inaddition, a flow control capability is provided via RTS/CTS signalingto disable a remote transmitter when the receiver buffer is full.

Also provided on the SC28L92 are a multipurpose 7-bit input portand a multipurpose 8-bit output port. These can be used as generalpurpose I/O ports or can be assigned specific functions (such asclock inputs or status/interrupt outputs) under program control.

The SC28L92 is available in two package versions: a 44-pin PLCCand 44-pin plastic quad flat pack (PQFP).