lbenson
Senior Member
5 years ago I made a PCB using a 14M2 to provide a serial interface (from another picaxe) to a 2x16 LCD with the Hitachi interface using Hippy's 4-bit code.
It worked (and works) fine. I had a use for it with a 4x20 LCD, so I plugged in the board. I thought it wasn't working, but happened to glance at it from an angle and could see the expected text very very faintly. I'm suspecting that it's because I tied pin 3 directly to ground (which had worked on my breadboard and worked on the LCD I first used). I see that some designs show this pin connected to a 10K pot. Can someone say what exactly this pin is supposed to do?
I can cut some traces and solder jumpers and a (say) 4K7 pullup to this pin if that is likely to help (if I can find a blank PCP after all these years--I'd rather not modify the one which works on the 2x16 LCD).
It worked (and works) fine. I had a use for it with a 4x20 LCD, so I plugged in the board. I thought it wasn't working, but happened to glance at it from an angle and could see the expected text very very faintly. I'm suspecting that it's because I tied pin 3 directly to ground (which had worked on my breadboard and worked on the LCD I first used). I see that some designs show this pin connected to a 10K pot. Can someone say what exactly this pin is supposed to do?
I can cut some traces and solder jumpers and a (say) 4K7 pullup to this pin if that is likely to help (if I can find a blank PCP after all these years--I'd rather not modify the one which works on the 2x16 LCD).
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