Yet another LCD problem...

Testing/Troubleshooting
1

Hello Midibox masters,

I’m reading a lot of LCD problems topics, but I can’t find a problem like the mine…

My LCD show nothing, no characters, but seems to be alive and backlight ok.

I get a 2*40 LCD model from “Topway” named LMB402CFC seems to be compatible with HD44780 standard.

It uses ST7066U chip, and datasheet precise KS0066 compatibility.

He is connected on a simple core module with PIC 18F452.

Fact one, LCD connection is fine, checked and checked tree times.

Fact two, PIC seems work perfectly, it sends me back a “F0 00 00 7E 40 00 01 F7” ACK midi message.

Fact tree (the worst), During testing with MIOS studio debug tool “one time”, I saw some characters without any sense…

I must precise that I also receive a yellow message in MIOS studio midi in when I boot the core module: [D0 1A 00] Channel 1: Channel pressure value 26

Any idea?

Thanks a lot Faton :wink:

2

Works fine with 16x2 LCD… 2x40 probably destroyed… :cry:

3

Works fine with 16x2 LCD… 2x40 probably destroyed… :cry:

Possibly, possibly not.

How are you connecting the LCDs to the core? is there any way you might have got that bit wrong?

You have determined by changing the LCD out, that the issue was not the Core, but could be either of the LCD; or the LCD cabling. This does not immediately mean the LCD is broken, it may still be a wiring issue between the Core and LCD. A short / bad wiring will occasionally show as garbled characters on the LCD.

see also here: http://www.midibox.org/forum/index.php/topic,11632

4

ok, thanks :wink: