These boards work really well. Need to pick an appropriate resistor value for the LED and this requires experimentation; blue vs red s greem being quite different. The one here is using 1k and is red.
This setup gives me a really minimalistic dual 7 seg module that has no need of clocks or anythng like that so it's a great fit for my needs.
The PICs inputs have pullups turned on so when the inputs are disconnected or high-Z then it shows "FF".
I noticed that in use the hi digit seemed to flicker even though in testing the 8 input bits ought have been typically 0 or momentarily high Z. Also, when the bus was switching between some known values I noticed flickers on segments that should have been constant on or off.
I figured that the samplng rate of the PIC was seeing those high Z moments, or sampling half way though switching delays, and displaying unwanted values.
I "fixed" this by adding a loop to the code where it only changes it's displayed value if the value on it's inputs was stable for a millisecond (or something like that). This way short blips and switching randomness don't mess up the display. Given that the high-Z moments are very short.
You can see what the V1 construction looks like here ...
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The outline is pretty small.
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The V2 board is in the post from China, but here's an image with the main points about the V1 board.
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Like I said in the previous post this is still a bit too big for my liking.
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