lcd 4x20 begin show strange chars

I have a RADDS controller with a RADDS display 20x4 arduino due R3 (printer 3d)

after few writes on arduino due on display begin show me only strange chars

on radds is an ttl logic converter I think HCT365 2L5E401 wich is between my arduino due and display

I'm not sure if that cip is broken, or display

strange is i see on display chars like &, % 2 and numbers on fist row some lines flashing ...

on the other side i think some library is taken wrong on compiling firmware arduino is updated on latest versions also libraries

any suggestion ?

any suggestion ?


Start by explaining what a “RADDS controller” actually is giving the Web links to the exact device, its schematics and specifications.

Also read the posting instructions and include your code.

Post the circuit diagram you are using and Web link to specifications of the display.

is a 3d printer

radds controller


repetier firmware

i attach schematic but what i found on internet

i don’t know which library are needed arduino to compile firmware

on display mast view x, y , z positions, also temperatures
i atach picture with how look now my display
some sings are changed due new writings chars on display send it by firmware but nothing normal

RADDS_26_sch.pdf (54.2 KB)

I haven't seen any of your code, because you didn't post it.

Yet i do have a tip:

Characters as well as variables are printed to your screen, not written.

I really appreciate you trying to post in English, but your posts are hard to read, they have a large "sinking about" (google it) part. You do know there's a German section (click!) too, don't you ?