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Character Display Module Explanations


#1

Hi guys,

I’m starting to work with 16x2 CharDisplay.
There are 2 methods for print text on display:


            char_Display.PrintString("TEST!") 
            char_Display.Putc(176)

In particular is interesting the method “Putc” because allows to print an ASCII character passing its decimal code.
This is the question: is supported Extended ASCII Table or not?

I tried to print the degrees char (°) but I can’t see it (the example above shows my attempt because 176 represents the extended ASCII table degrees char value). The display shows a minus char (-).


#2

I haven’t looked at the code of the driver, or used it, but I would expect that you need to worry about the code that corresponds to the character, not the standard ASCII code… see something like http://shop.tuxgraphics.org/electronic/tuxgr_blue16x2_charset.png as an example of the standard character set. Edit: I see 176 is also the degrees symbol - time to dig into the driver code :slight_smile:


#3

the display uses a display chip which is identified in the developers guide. find the data sheet for the chip. it should answer your question.


#4

Thanks for both replies, they’re useful! ;D

Another question: is it possible to paint custom characters using the standard driver?
(I worked with a similar char display programming in C++ and I could paint custom characters by setting dots on and dots off manually) .


#5

If I remember the specs correctly you can define/design your own char set, but setting individual pixels is not possible.


#6

@ Reinhard Ostermeier - Thanks for reply. It is exactly what I wanted to mean: a custom charset.

How can I define my own charset? Can you give me a tip?


#7

You should look for the data sheet / docs of the Controller chip. Haven’t done this my self.


#8

lots more if you use a search engine, look for “hd47780 datasheet”


#9

The controller also allows for 8 custom symbols/chars. I have a modified driver here someplace that I wrote to allow for setting and using the custom chars. I’ll clean it up and post it later on :slight_smile:


#10

Thanks to all for replies.

@ Brett - I found this link that lists all characters that HD44780 accepts (personally tested): http://symlink.dk/electro/hd44780/lcd-font.png

@ danibjor - That’s great! I’m courious to see your code! :slight_smile:


#11

@ BigFoot - Here you go!

https://www.ghielectronics.com/community/forum/topic?id=13917


#12

@ danibjor - great, excellent! Thank you very much!!