UPSD3212A Datasheet, PDF (44/163 Pages) STMicroelectronics – Flash Programmable System Devices with 8032 MCU with USB and Programmable Logic

uPSD3212A, uPSD3212C, uPSD3212CV
OSCILLATOR
The oscillator circuit of the uPSD321x Devices is a
single stage inverting amplifier in a Pierce oscilla-
tor configuration (see Figure 19). The circuitry be-
tween XTAL1 and XTAL2 is basically an inverter
biased to the transfer point. Either a crystal or ce-
ramic resonator can be used as the feedback ele-
ment to complete the oscillator circuit. Both are
operated in parallel resonance.
XTAL1 is the high gain amplifier input, and XTAL2
is the output. To drive the uPSD321x Devices ex-
ternally, XTAL1 is driven from an external source
and XTAL2 left open-circuit.
Figure 19. Oscillator
XTAL1
XTAL2
8 to 40 MHz
XTAL1
External Clock
XTAL2
AI06620
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