SCC2691AC1D24 Electronic IC Chips Universal asynchronous receiver

SCC2691 Universal asynchronous receiver/transmitter (UART)

DESCRIPTION

The Philips Semiconductors SCC2691 Universal Asynchronous Receiver/Transmitter (UART) is a single-chip CMOS-LSI communications device that provides a full-duplex asynchronous receiver/transmitter. It is fabricated with Philips Semiconductors CMOS technology which combines the benefits of high density and low power consumption.

The operating speed of the receiver and transmitter can be selected independently as one of 18 fixed baud rates, a 16X clock derived from a programmable counter/timer, or an external 1X or 16X clock. The baud rate generator and counter/timer can operate directly from a crystal or from external clock inputs. The ability to independently program the operating speed of the receiver and transmitter make the UART particularly attractive for dual-speed channel applications such as clustered terminal systems.

The receiver is quadruple buffered to minimize the potential of receiver overrun or to reduce interrupt overhead in interrupt driven systems. In addition, a handshaking capability is provided to disable a remote UART transmitter when the receiver buffer is full.

The UART provides a power-down mode in which the oscillator is frozen but the register contents are stored. This results in reduced power consumption on the order of several magnitudes.

The UART is fully TTL compatible and operates from a single +5V power supply.

FEATURES

• Full-duplex asynchronous receiver/transmitter

• Quadruple buffered receiver data register

• 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

• Baud rate for the receiver and transmitter selectable from:

  – 22 fixed rates: 50 to 115.2K baud

  – Non-standard rates to 115.2kb

  – Non-standard user-defined rate derived from programmable timer/ counter

  – External 1X or 16X clock

• Parity, framing, and overrun detection

• False start bit detection

• Line break detection and generation

• Programmable channel mode

  – Normal (full-duplex)

  – Automatic echo

  – Local loopback

  – Remote Loopback

• Multi-function programmable 16-bit counter/timer

• Single interrupt output with seven maskable interrupting conditions

• On-chip crystal oscillator

• Low power mode

• TTL compatible

• Single +5V power supply

• Commercial (0°C to +70°C) and industrial (-40°C to +85°C) temperature versions available

• SOL, PLCC and 300 mil wide DIP packages available

ABSOLUTE MAXIMUM RATINGS¹

NOTES:

1. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other condition above those indicated in the operation section of this specification is not implied.

2. For operating at elevated temperature, the device must be derated based on +150°C maximum junction temperature.

3. This product includes circuitry specifically designed for the protection of its internal devices from damaging effects of excessive static charge. Nonetheless, it is suggested that conventional precautions be taken to avoid applying any voltages larger than the rated maxima.

4. Parameters are valid over specified temperature range. See Ordering Information table for applicable operating temperature and V_CC supply range.

PIN CONFIGURATIONS

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