DESCRIPTION

The 68C94 quad universal asynchronous receiver/transmitter (QUART) combines four enhanced Philips Semiconductors industry-standard UARTs with an innovative interrupt scheme that can vastly minimize host processor overhead. It is implemented using Philips Semiconductors’ high-speed CMOS process that combines small die size and cost with low power consumption.

FEATURES

• New low overhead interrupt control

• Four Philips Semiconductors industry-standard UARTs

• Eight byte receive FIFO and eight byte transmit FIFO for each UART

• 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

• Baud rate for the receiver and transmitter selectable from:

– 23 fixed rates: 50 to 230.4K baud Non-standard rates to 1.0M baud

– User-defined rates from the programmable counter/timer associated with each of two blocks

– 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 loopback

• Programmable interrupt priorities

• Identification of highest priority interrupt

• Global interrupt register set provides data from interrupting channel

• Vectored interrupts with programmable vector format

• IACKN and DTACKN signals

• Built-in baud rate generator with choice of 18 rates

• Four I/O pins per UART for modem controls, clocks, etc.

• Power down mode

• High-speed CMOS technology

• 52-pin PLCC and 48-pin DIP

• Commercial and industrial temperature ranges available

• On-chip crystal oscillator

• TTL compatible

• Single +5V power supply with low power mode

• Two multifunction programmable 16-bit counter/timers

• 1MHz 16x mode operation

• 30ns data bus release time

• “Watch Dog” timer for each receiver