Will Annex support this?

[Electroguard]

Looks like the i2c device is being addressed ok, and the display is displaying just on line 1, so it is evidently partially working.
I would start by buzzing out continuity of the serial to parallel wiring, and checking for shorts between neighbouring pins.
If ok, try writing only a couple of chrs somewhere partially along line 2 to see if that tries to work.
If still trying to work but sending incorrect chars, perhaps LCD character set has been corrupted, so might be worth defining a custom character and trying to display that by itself.

Even if the hardware is faulty it Is not the end of the world, cos those displays are available very cheap, with a choice of display colours.
(probably best to get a 2004 [4 lines of 20 chrs] with the serial to parallel converter already soldered)

[bugs]

I hooked up an esp8266 with my 4 -line display and pasted in your code - changing only the I2C pins to 4 & 5 to suit.

[Zim]

This is what I got with a "heart" symbol....
Might be time to adjust it with a hammer!
The screen was salvaged from a older chinese signal generator. Maybe it has some oddball programing?

Resized_20240210_112835.jpg

[Electroguard]

Well that certainly explains things, cos the chinese and english alphabets are a bit different !
But at least it got you a working familiarity with the LCD displays, which are cheap, and only need 2 gpio's to use.

lcd2004.jpg

[Zim]

Thanks Electroguard

Are they all visible without a backlight?

[Electroguard]

It's the backlight colours which makes the displays very noticeable, so I've had no reason to try without a backlight, but without the backlight it would probably be the same as seen in your 'hearts' character pic.

The LED backlight can be enabled/disabled by a 'tombstone' jumper link on the serial to parallel interface - so you should be able to arrange for the backlight LED to only be lit by PIR or radar sensor proximity if wished.

[Zim]

AAAAhhhhhhhh so thats what that little jumper is for! Thanx!

Zim

[bugs]

My 4 line display is invisible without the led on.
This prog prints all the character set to the LCD (and serial port) so might help spotting a stuck bit or something...

Code: [Local Link Removed for Guests]

'test LCD character set 0 to 255

I2C.SETUP 4,5 ' set I2C port on pins 21 and 22

LCD.INIT 39, 16, 2
LCD.CLS  ' clear the screen of the LCD

'print a message on the LCD at the first char of the first line
for j=0 to 15*16 step 16
  wd$=""
  for i=0 to 15
    wd$=wd$+chr$(i+j)
  next i
  print j,wd$
  LCD.CLS
  LCD.PRINT 1, 1, wd$
  pause 1000
next j

end