wiring diagram incl with CrystalControl


New member

Just bought my new Crystalfontz display and was taking a look at the HD44780 wiring guide included with the Crystal Contol software.

For wiring up the power, the guide says:

Solder a moderatly long piece of black wire from pin 24 of the DB25 connector.

But the wiring table shows ground being wired from pin 25.

And also, my parallel cable only has 18 wires, pins 18-24 aren't connected to anyting.

So should I wire ground to pin 24, or 25?

Also, the wiring guide for the 100 Ohm pot only describes a connection from pin 2 and pin 1(or 3). Do I just cut off the other pin?

Thanks for the info.

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Which model of display are you using?

Use pin 25 as ground. Older printer cables have pins 18-25 as ground. Then they got cheaper and eliminated the unused wires.

The standard contrast circuit uses a 10Kohm pot, not 100 ohm. The two outside pot terminals go between pins 1 & 2 on the display. The center terminal goes to pin 3 on the display.
The backlight uses the 100 ohm pot, using the center and one outside terminal, no need to cut off the unused terminal, but you could connect the unused terminal to the center terminal, it doesn't matter.