1602 LCD-Screen not configured correctly
Started by Dennio




3 posts in this topic
hansehv

168 posts 17 threads Joined: Dec 2020
11-03-22, 22:50 -
#2
Hi Dennio,
It looks like HD44780 to me, giving the appearance and the way the connections are ordered.
I have encountered wrong characters under next different circumstances:
  1. wrong wiring (double use of pins, wrong pins, short circuitry)
    Your picture has similarities with this.
    But you already checked and double checked, so...
  2. insufficient power supply, but that looks more like "chinese" - in my case that is, but these displays are produced by multiple suppliers. Same goes for next:
  3. restarting without full power off of PI. This can be tricky: you can pull the power supply but still have an hdmi screen connected supplying power.
    In this case the init of the display fails for a reason I haven't found yet.
The GPIO of PI4 is supposed to be the same. I've never actually tested this variant though.

A small option might the PI4 speed. The display must be initialized (=showing blocks on the first line, blanks on second) before samplerbox starts using it (using both lines). On the 3B+ and lower you can clearly see that happen.
Samplerbox is started and usable very early in the startup process. You can be playing before the linux commandline is available. Webgui is the last thing becoming available.

By the way: a two line display does not exactly look like what is shown in the webgui because that assumes it has at least 3 display lines for the menu - in practice a 4-or-more line display.
A 16x2 display has just two lines for the menu plus additional messages, so the display will show the most important lines only.
You'll see and understand once you have the display working - you can use display and webgui simultaneously.

This won't really get you going I'm afraid, but it's all I can say from this distance,
Hans


Messages In This Thread
RE: 1602 LCD-Screen not configured correctly - by hansehv - 11-03-22, 22:50