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Topic: Problem with LCD and Motor (Read 10 times) previous topic - next topic

dc42

#20
Jan 22, 2012, 03:39 pm Last Edit: Jan 22, 2012, 05:50 pm by dc42 Reason: 1
My recommendation is to connect the ground line locally on the board instead of off-board. Take the ground feed to the Arduino from the -ve side of that 1000uF capacitor, so that capacitor leg is the junction between the wires to mosfet source, power supply ground, and Arduino ground. This will help to minimize switching noise feeding back to the Arduino. Also connect a 0.1uF ceramic capacitor in parallel with the 1000uF.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

wbegg

Will do. Thank you so much for your help. I will be isolation routing this today on the CNC.

wbegg

This seems to have solved the problem, but now I just found a new one with my LCD display.

When I turn the contrast down - with 10K pot - below a certain level, and back up again, It displays strange characters, and must be reset. This is regardless of whether I have the logic pins connected or not. It's not a big issue, as I leave it turned up anyway, but just curious as to what could be causing this.

This is after an hour of wondering why the contrast didn't adjust at all only to find out the pin2 and pin 3 are swapped on my particular HD44780 compatible LCD (JHD204A - made in China).

floresta

#23
Jan 23, 2012, 06:38 pm Last Edit: Jan 23, 2012, 06:40 pm by floresta Reason: 1
Quote
but just curious as to what could be causing this.

You may have the potentiometer miswired so that it is shorting the power supply (and overloading the potentiometer) when you turn it to one end.

Quote
This is after an hour of wondering why the contrast didn't adjust at all only to find out the pin2 and pin 3 are swapped on my particular HD44780 compatible LCD (JHD204A - made in China).

I doubt it.  Are you sure you haven't misinterpreted or miswired the potentiometer pins.

Don

liudr

Sorry I ran away while everyone else here is kicking the ball. Could you post some hi-res pictures of how you connected the pot? I have the same suspicion as floresta. Unless you supply a picture, nobody can be sure you connected the wires correctly. Is it possible that pins 2 and 3 or pins 1 and 2 are shorted with solder bridge?

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