DESCRIPTION The Epic Ei68C684/Ei88C684 Quad Universal Asynchronous Receiver and Transmitter (QUART) is a data communication device that provides four fully independent full duplex asynchronous communication channels in a single package. The QUART is designed for use in microprocessor based systems and may be used in a polled or interrupt driven environment. FEATURES • Full duplex, four channel asynchronous receiver and transmitter • Quadruple-buffered receiver and transmitter • Internal bit rate generator with 23 industry standard bit rates operating from either of two standard crystal clocks • Independent bit rate selection for each receiver and transmitter • Maximum bit rate: 1 x clock - 2 Mb/sec., 16 x clock- 250 Kb/sec. • Normal, auto-echo, local loop-back and remote loop-back modes • Multi-function 16-bit counter/timer • Programmable interrupt daisy chain • Up to 32 I/O pins (depending on package and version) • Change of state detectors on inputs • Multidrop mode compatible with 8051 ninebit mode • Stop bits programmable in 1/16-bit increments • Pin selectable 88xxx/68xxx interface • Debounced reset pin (20 nsec. min) • On-chip oscillator for crystal • Programmable internal clock:X1/CLK or X1/CLK divided by 2 • Buffered system clock output pin • Stand-by mode to reduce operating power • Advanced CMOS low power technology
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