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adafruit / Adafruit-LED-Backpacks

PCB files for Adafruit LED Backpacks
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Pin numbering on 1.2" 7-segment clock display? #2

Open adamwolf opened 4 years ago

adamwolf commented 4 years ago

Hi folks!

@matthewbeckler and I were having trouble interpreting the schematic and PCB, because they didn't seem to match around the first two pins of the display. I opened up the source files in my editor, rather than the exported images, and I noticed that the pins for the display are not in numerical order.

Screenshot 2019-12-19 09 42 45

I'm curious what the reasoning is for this. If this was a mistake, is there some way I can help fix it or would that involve internal libraries or something?

Anyway, thanks for all the good work!

Docteh commented 3 years ago

I ran into this just today looking at the various board layouts.

The PCB file is consistent with the shipped product, so the top pin does connect to Pin 4 of the HT16K33, and the second pin (labeled pin 1 on the PCB) goes to Pin 2 on the HT16K33.

Another interesting quirk is that the PCB layout appears to show the rectangle bleeding off of the board, but on the actual product the silk screen lines are on the board.

ShearonA commented 2 years ago

This took me way longer to find than it should have. As the previous two people have identified, the board is correct, but the schematic is incorrect. The schematic shows the decimals/colons being connected to COM0, and they are connected to COM2, with digit 1 (of 4) being connected to COM0, digit 2 (of 4) being connected to COM1, digit 3 being connected to COM3, and digit 4 being connected to COM5.

It doesn't matter if one is using the Arduino libraries, but if you are building your own library in C, this will take a while to figure out that your code won't work if you program to the schematic.