crystals powering multiple devices (bit-bang simulation of SPI)

Dilithium crystal and Scotty jokes to follow...

Tim.

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In general you CAN use a crystal to clock (not power) more than one device. You use the xtal controlled oscillator of device one and take a clock output from device one to drive the clock input of device two. If there is not a clock output or input, you may with caution, take the driven terminal of the xtal on device one as the clock output and connect it to the xtal input of device two. It may require some series resistance to limit the drive level. Do not connect the xtal drive pin of device two. For parallel mode crystals, the shunt capacitors should be reduced in value to reduce crystal loading by the added circuitry. In some cases, buffering may be required depending on the specific circuit.

Another option is to use a ready made xtal oscillator instead of an xtal and connect it's output to the two clock or xtal inputs on the two devices. A

Yes, it's possible to use one crystal to clock multiple devices provided that the clock signal is suitably 'strong' or adequately buffered.

You may want to look at this Intel application note. It's very useful.

Graham