Description

The SC28L91A1A is a single channel UART from the IMPACT family of Serial Communications Controllers. It operates at 3.3 and 5.0 volts Vcc, with 8 or 16 byte FIFOs. The SC28L91A1A is highly compatible with software of the SC28L92 and previous UARTs offered by Philips. It is an improved version of the previous one channel part and comes with a range of enhancements, including a 16 character receiver, 16 character transmit FIFOs, watch dog timer for the receiver, mode register 0, extended baud rate options, faster bus and data speeds, programmable interrupt capabilities for the receiver and transmitter, and a versatile I/O structure. Please note that the previous one channel part, SCC2691, is not being discontinued.

Specifications and features

• Member of IMPACT family: 3.3 to 5.0 volts, –40°C to +85°C and 68K for 80xxx bus interface for all devices.
• A full-duplex independent asynchronous receiver/transmitter.
• 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 transmitter selectable from:
• 28 fixed rates: 50 to 230.4 k baud.
• Other baud rates to 1 MHz at 16X.
• Programmable user-defined rates derived from a programmable counter/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 interrupting conditions.
• Output port can be configured to provide a total of up to six separate interrupt outputs that may be wire ORed.
• Each FIFO can be programmed for four different interrupt levels.
• Watch dog timer for the receiver.
• Maximum data transfer rates: 1X – 1Mb/sec, 16X – 1Mb/sec.
• Automatic wake-up mode for multi-drop applications.
• Start-end break interrupt/status with mid-character break detect.
• On-chip crystal oscillator.
• Power down mode.
• Receiver time-out mode.
• Single +3.3V or +5V power supply.

Application Scenarios

The SC28L91A1A UART can be used in a variety of applications, including:

• Serial communication between devices.
• Industrial automation.
• Data logging.
• Embedded systems.
• Remote monitoring.

Comparison

• High compatibility with software of previous UART models.
• Improved features, such as 16 character receiver and transmit FIFOs.
• Versatile I/O structure for flexible integration.
• Programmable interrupt capabilities for receiver and transmitter.
• Wide range of baud rate options.
• Fast data transfer rates.
• Power down and receiver time-out modes for energy efficiency.

• May not be suitable for applications requiring multiple channels.
• Limited to a single +3.3V or +5V power supply.