DESCRIPTION

The 28L202 is a high performance dual UART. Its functional and programming features closely match but greatly extend those of previous Philips dual channel UARTs. Its configuration on power up is similar that of the SC26C92. Its differences from the SC26C92 are: 256–character receiver, 256 character transmit FIFOs, 3 and 5 volt compatibility, 8 I/O ports for each UART – 16 total, arbitrating interrupt system and overall faster buss and data speeds. It is fabricated in an advanced 0.5 micron CMOS process that allows stand by current of less that 10 microamperes.

FEATURES

• Member of IMPACT family: 3.3 to 5.0 volt , –40°C to +85°C and 68K for 80xxx bus interface for all devices.

• Dual full–duplex independent asynchronous receiver/transmitters

• 256 character FIFOs for each receiver and transmitter

• Powers up to 9600 baud, 1 stop bit, no parity, 1 stop bit, interrupt disabled, all I/O set to input.

• Pin programming to 68K or 80xxx bus interface

• Three character recognition system per channel, used as:

– General purpose character recognition

– Xon/Xoff character recognition

– Address recognition Wake up (multi–drop or “9 bit”) mode

– System provides 4 levels of automation on a recognition event

• Programmable data format

– 5 to 8 data bits plus parity and 9 bit mode

– Odd, even, no parity or force parity

– 9/16,1, 1.5 or 2 stop bits

• 16–bit programmable Counter/Timer

• Programmable baud rate for each receiver and transmitter selectable from:

– 27 fixed rates: 50 to 2.0 Meg baud (includes MIDDI rate)

– Other baud rates via external clocks and C/T

– 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 8 bit I/O input port per channel loosely assigned to each channel.

– Can serve as clock or control inputs

– Change of state detection on eight inputs

– Inputs have typically >100Mohm pull–up resistors

– Modem and DMA interface

• Versatile arbitrating interrupt system

– Interrupt system totally supports ‘single query’ polling

– Output port can be configured to provide a total of up to six separate interrupt type outputs that may be wire ORed (switched to open drain).

– Each FIFO can be independently programmed for any of 256 interrupt levels

– Watch dog timer for each receiver

• Maximum data transfer rates: 1X – 3 Mb/sec, 16X – 2 Mb/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 at less than 10 µa

• Receiver time–out mode

• Single +3.3V or +5V power supply