COSMAC Elf switch panel using PCBs

Eric Smith spacewar at
Sun Apr 24 00:38:22 CDT 2016

On Sat, Apr 23, 2016 at 8:18 PM, dwight <dkelvey at> wrote:
> You'd need to decide, LOAD is switch up or
> LOAD is switch down.

Which still doesn't explain how a toggle (not momentary) can be said
to have NC and NO pins. But at this point I'm flogging a dead horse.

> Even if a single wire, it needs to be debounced.

Yes. Elf2K uses both contacts with an S-R FF. My other system is VHDL
in an FPGA and has a counter-based debouncer.

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