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Multiple digits driven by a single decoder, like on the clock radios. I wanted to see if EveryCircuit can be fast enough for convincing persistence of vision. Its not great I think that's down to mismatch of the refresh and the speed of the cycling. If you getting missing digits, try slow down the sim speed and speed up again.
nikkisalli (you still around?) had done something like this way back, but it was sluggish on EC then. Seems a lot faster now if using the right components.
Couldn't use the 7digit displays in EC cos can't access their cathodes, which is needed for the multiplexing in this circuit.
The 7 outputs of the decoder are connected to the segments of all 4 numbers in parallel.
The logic on the right is just there to start off the shift registers cycling correctly. It clocks the 'counter/shiftregisters' back twice to 14 (binary 1110).
The registers continously shift the '0' round, pulling low the cathodes of each number cycling very fast.
The decoder counts 0 to 3 instep with the cycling. The clock generator is the fastest possible in EC (I think), self toggle inverter through 2 buffers (to increase the propagation so that the inverter starts toggling ).
Have a go getting the numbers in the right order 0123 by tapping the switch in the middle. This temporarily unlinks the cycling from the clock.
You may notice I have wired up the shifting and the counting to the same timing of the clock. Realistically there should be a slight latency between the shifting and counter being displayed. But in EC the latency/propagation delays don't seem to apply to the shiftregisters/counter and the 7digit decoder, they only apply to the logic gates and the flipflop latches (that's what I've found anyway)
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