XR82C684CJ-F Datasheet, PDF (56/107 Pages) Exar Corporation – CMOS Quad Channel UART(QUART)

XR82C684

7  N & S 9

7  N & S 9
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7   9 N & S 9

7   9 N & S 9

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Figure 29. Recommended Schematics for the XTAL Oscillator Circuitry
Note: The user also has an option to drive the Oscillator Circuit with a TTL input signal, in lieu of using a crystal oscillator.
If this approach is used, the TTL must be driven into the X1/CLK pin, and the X2 pin must be left floating.
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Figure 30. A Recommended Schematic to Drive Multiple QUARTs from the Same Crystal Oscillator
Note: The user is urged not to use the 74LS14 Schmitt Trigger Inverter in lieu of the 74HC14 device. The input of the
74LS14 tends to load down the oscillating signal from the QUART, to the point that the Schmitt Trigger inverter
can no longer change state or respond to the oscillator signal.
 
9.