I buy a 2x40 LCD on ebay (I will ask for the datasheet), with a HD44780 chip. I plug it on the core and… It works, but some character are not the right one! 0 (zero) is a bold ‘i’, the x, a, p, l, e (lower case) are some weird character (I look at the HD44780 datasheet, and didn’t find all of them!). the lower case ‘m’ is correct. All the Upper case are correct (I think, I test running the AIN example 2).
Any idea??? I check the wiring manytimes, but I may be made a mistake (with no datasheet, I only found a wiring on a forum)…!
is it possible to test them with a MIOS test program (or should I write this one?)
But I think it’s weird that it display 1,2,3,4,5,6,7,8,9 but not 0?
In the hd44780 datasheet, somme of the character are in the A02 eprom, this would agree what you said?
By the way, they’ve got no backlight… I didn’t think it was a drawback when I order them (they were “cheap”), but it’s make about 4hour that’s I’m looking for a way to add this… and I think it’s impossible… if anyone as an idea, tell me, but I’m now looking for other LCD!
thanks Thorsten! I think I’m going to test all the character that can be displayed!
(my midibox LC is growing and working well ;)… with a 2x20 LCD…)
huumm so I look closer to the hd44780 datasheet, and with the japanese character set (rom code A00) the a,b,c,d,e… ect Lower and Upper Case have the same code as in the european character set (rom code A02)… so?
I re-check my wiring, and it’s seems to be good, but I think if I made a mistake on the data bus, there will be other errors, no?
Well, I try to make a test program, but it’s hard because i use Emacs, gpasm, perl under linux, and then I have to boot under windows to send it with MIOX… I will be happy when the java client for uploading apps will be finish
And is there any way to get the display brighter? I test with putting some led in front of it but it’s make no difference… I’m asking why LCD with no backlight exist!
By the way, thanks Thorsten, because it’s very easy and interesting to work with MIOS ;D
Yes, you could try to find out the exchanged data lines by printing different chars. I can suggest two solutions:
If you like the Unix feeling (like me! :-)), just install Cygwin (http://www.cygwin.com), this is a nearly complete Unix environment running under Wintendo. Perl and Emacs are part of the standard release (the setup program allows you to select all the programs which you would like to use, thereafter the appr. packages will be downloaded and installed automatically)
Another, maybe faster solution for the first tests: you are able to execute any function via MIDI by using the debug feature which is integrated into MIOS.
I just have inserted this tool into the MIOS release
Search in mios_vectors.inc for the address of the appr. function. Or search in the .lst file if an application function should be executed. Run the mkdbg.pl script with the appr. parameters and send the generated SysEx string to the core.
clear the display - the address of MIOS_LCD_Clear is 0x2d04. Start the mkdbg.pl script with following parameters:
I only unix like feeling I have test cygwin some times ago… but it’s still windows…
Oki I 'm going to make my midi port works under linux (with alsa, i have still some problem with…) and test the LCD via function! I think it’s the easiest way to test it! (because writing a test program will take a lot of time, as I don’t know asm very well… only x86)
Unfortunately the return messages of a debug command will not be received (too fast) - possibly I’ve to rewrite the receive handler so that input and output streams are handled in parallel. However, something for the next days…
;D
