DESCRIPTION
The XR68C92/192 is a Dual Universal Asynchronous Receiver and Transmitter with 8 (XR68C92) or 16 (XR68C192) bytes of transmit and receive FIFOs. The XR68C92/192 is pin-to-pin and functionally compatible to the XR68C681 and Philips SCC68681 UART with additional features. The operating speed of the receiver and transmitter can be selected independently from a table of twenty four 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 input. The XR68C92/192 provides a power down mode in which the oscillator is stopped but the register contents are retained. The XR68C92/192 is fabricated in an advanced CMOS process to achieve low power and high speed requirements.

FEATURES
• Pin to pin and functionally compatible to XR68C681 and SCC68692
• Full duplex transmit and receive operation
• 8 bytes of transmit/receive FIFOs (XR68C92)
• 16 bytes of transmit/receive FIFOs (XR68C192)
• Programmable character lengths (5, 6, 7, 8)
• Parity, framing, and over run error detection
• Programmable 16-bit timer/counter
• On-chip crystal oscillator
• Single interrupt output with eight selectable interrupting conditions
• External 1X or 16X clock
• Data rate up to 1Mbps
• Independent transmit and receive baud rates from 50bps to 230.4kbps
• 6 General purpose inputs
• 8 General purpose outputs
• TTL compatible inputs, outputs
• 4 Transmit/receive trigger levels
• Watch dog timer
• Multi-drop mode compatible with 8051 nine bit mode
• 3.3 or 5 volts operation
• Loopback modes
• Power down mode