LCD Custom Character Library (ASCII, unicode, etc.)
What type of character library (e.g. ASCII, unicode, etc.) does Prusa firmware use/allow for the LCD screen? I'm trying to modify the Printer Display through the OctoPrint Display Layer Progress plugin and keep getting ????? instead of a right arrow (I've tried 🡆▶➔→»).
RE: LCD Custom Character Library (ASCII, unicode, etc.)
The character set on the printer is extremely limited because of the hardware used. I think the LCD display in the RepRap Smart Controller supports a basic ASCII character set and allows for 8 custom characters to be defined by the firmware that is driving it. These are used for the symbols like the thermometer, heat bed, folder, clock, navigation arrows etc. All the custom characters are defined in the ASCII control character range, but as far as I know there isn't any way to send control characters to the printer using a Code M117 command. Unknown characters just get a '?' as you have already seen.
I had a play around in the OctoPrint terminal and found that the ASCII '>' character is supported (use M117 >) and that the '~' symbol is mapped to a 'right arrow' (enter M117 ~) - your lucky day!
There may be other standard ASCII characters that have a non-standard mapping, so I suggest to have a play around with the M117 command if you have time.
Cheers,
Tim
RE: LCD Custom Character Library (ASCII, unicode, etc.)
Thank you! Strange that the tilde (~) is actually a right arrow, but that worked. Also, I tried all of the keystrokes available on my keyboard using M117. They all worked except for these * ' ; and ~ is a ➔ (as discovered above) and \ is a ¥.
RE: LCD Custom Character Library (ASCII, unicode, etc.)
My pleasure! I was also looking at the M117 command a little while back and wondering what was possible. Your post pushed me to dig a bit deeper - so all in all, it was a good learning exercise for me as well.
Cheers,
Tim