XR-88C681

XR-88C681 is a kind of CMOS Dual Channel UART (DUART) which provides two fully independent full duplex asynchronous communications channels in a single package.It is designed for use in microprocessor bases systems and may be used in a polled or interrupt driven environment.

There are some features of XR-88C681 as follows.First is stop bits programmable in 1/16-bit increments.The second is internal bit rate generator with 23 bit rates.Then is independent bit rate selection for each receiver and transmitter.Next is normal, autoecho, local loopback, and remote loopback modes.The fifth is multi-function 16-bit counter/timer.The sixth is interrupt output with eight maskable interrupting cond.The seventh is programmable interrupt daisy chain.The eighth is on-chip oscillator for crystal.The ninth is multidrop mode compatible with 8051 Nine-Bit mode.The tenth is standby mode to reduce operating power.The last one is advanced CMOS low power technology.

What comes next is the absolute maximum ratings of XR-88C681.The storage temperature is from 65 to +150.All voltages with respect to ground is from 0.5 to +7.0 V.Then is about the DC electrical characteristics (TA=0 to 70,VCC=5.0 V±5%).The minimum VIL (input low voltage) is -0.5 V and the maximum is 0.8 V.The minimum VIH (input high voltage) is 2.0 V and the maximum is VCC V except X1/CLK.The minimum VIH1 (input high voltage) is 4.0 V and the maximum is VCC V for X1/CLK.The maximum VOL (output low voltage) is 0.4 V at IOL=2.4 mA.The minimum VOH (output high voltage) is 2.4 V at IOH=-400 A except open drain outputs.The minimum IIL (input leakage current) is -10A and the maximum is 10A at VIN=0 to VCC.