Closed Koepel closed 2 years ago
I found the bug because of this topic in the Arduino forum: https://forum.arduino.cc/t/lcd-display-not-working-correctly/981088/ As you can read over there, the correct way for the contrast is a potentiometer of 1k to GND (not to 5V). A selected fixed resistor will also often work.
Almost everyone does it wrong in the real world, but that does not mean that we can't do it right in a simulation. This is the right way (no 5V to the potentiometer):
Thanks for pointing this out!
We do not simulate contrast at the moment (maybe we should? I think can be more confusing than helpful, but that's just my opinion).
I'll switch the backlight to be controlled by the A/K pins (not sure why I mixed them up with V0 at the first place)
I'll switch the backlight to be controlled by the A/K pins (not sure why I mixed them up with V0 at the first place)
Done, mind having a look?
p.s. thanks for creating this awesome reproduction playground, it's really helpful!
It works. Thank you.
I found the limit. The internal pullup resistor of a Arduino Uno with pinMode( pin, INPUT_PULLUP)
can turn the backlight on when directly connected to the Anode. When there is a resistor to the Anode, then it does not turn the backlight on.
Contrast simulation is not needed.
A normal LCD display (not with I2C backpack) has a contrast pin 3 called "V0". Often a 10k potentiometer is used for it. It is little known that it has a internal resistor to a positive voltage, therefor a resistor to GND is all that is needed for the contrast.
Here is my test project: https://wokwi.com/projects/328962883622797906
The contrast should not control the backlight and the display should work with the two used circuits (potentiometer at V0 or a resistor to GND).