Does SamplerBox work with 20 X 4 LCD screens?

Instructions/documentation says SamplerBox works with 20 X 4 LCD screens -- Is this an error/incorrect?

Confirm it works, that is: with I2C-HD44780.
You have to configure "USE_I2C_LCD = 20x4" in the configuration.txt.
See docs.

[quote pid="589" dateline="1751125754"]
Confirm it works, that is: with I2C-HD44780.
You have to configure "USE_I2C_LCD = 20x4" in the configuration.txt.
See docs.
[/quote]

Yes, I have "USE_I2C_LCD = 20x4" in the configuration.  The output is still utilizing only 2 lines and 16 characters (16x2).  The other lines/characters are unused/blank.


Can you clarify, by "Confirm it works", do you mean A. "I see it in the docs, so it should work", or B. "I'm personally using a 20x4 screen" ?

Hi,

This gets interesting as this could be the first confirmation of 4 working lines.
So @guest: can you please confirm its indeed 4 lines and whether you had to do something extra. Many thanks !

I've introduced this coding in may 2020 with a note in the changes.txt:

Code:

  - Added I2C-LCD (HD44780, 2x16 and 4x20).
    Support is theoretical as I can't test this, please feedback results.

Several users have struggled to get it working with 2 lines, in most cases solved with checking wires or the backlight screw (please search the forum for the applicable threads if you want to see all details).

There's only one feedback regarding 4 lines: s1100 (unregistered user) reporting "not working for4 lines, only 2", with a typical detail:

Config info:
"USE_I2C_LCD = True" --> displays 16x2
"USE_I2C_LCD = 20x4" --> no output
"USE_I2C_LCD = 16x2" --> no output

("USE_HD44780_16x2_LCD = False" in all cases)

At that time I was absent, but looking at it now, the "16x2 no output" intrigues me as this suggests a coding error, however I cannot reproduce this. Lacking this hardware I can only perform "dry" tests.

@RaspberryP99: Do you have the same?
If so: would you be so kind to register as forum user, so that I can can send you some test/debug material via private messages that would help in finding a fix.

Regards, Hans

Hi Hans,
Yes, it outputs 16x2 to the 20x4 screen while using:
USE_I2C_LCD = True

The output shows on the Top 2 lines, while the bottom 2 lines are blank (as well as the last 4 characters), eg:

xxxxxxxxxxxxxxxx____
xxxxxxxxxxxxxxxx____
____________________
____________________

Changing to "USE_I2C_LCD = 20x4" as the Guest recommended results in a blank screen.

Upon re-reading the Guest's post, I think by "Confirm it works", they may have intended to say "Make sure your screen is functional", rather than "Yes I am confirming that 20x4 works" ?

If you have an alternate build, I can test it on my screen.