NP-41 Emulator (may be)

[Chris Chung]

Tried to lower the frequency but did not help much. I did get rid of a lot of the ghosting by lowering the supply voltage from 3.3V to 2.9V.



The LCD were ordered to have VLcd at 3.0V as I intend to run the calculator off a 3V coin cell, which I was doing on the photo, except I add a potentiometer to drop it further to 2.9V. When I get the charge pump to work, I can make it software configurable.

It is readable but does not have high contrast, as it's 6-MUX so I will have live w/ that. There are still a few odd ghosted segments with probably was introduced by my poor soldering.

I will start to implement the keyboard scanner.

/EDIT embedded image doesn't seem to work. upload this one