Help needed, LCD not working / initialising.

[latency_]

Hi there,

Wondered if you folks could give me a hand troubleshooting an LCD I've just assembled.

I have this LCD: eBay link

Which is a bog-standard 4x20 LCD with the Hitachi controller, and I've soldered it up to this USB piggyback board: eBay link

Based on my interpretation of the piggyback board instructions, I've connected the LCD to pins 3 to 18 of the USB board like so:

Code: Select all

LCD: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

USB board:

15 16
13 14
11 12
9  10
7  8
5  6
3  4
1  2
nc nc

I've successfully installed the windows driver for the USB board, but when I connect it, instead of seeing the initialise screen, I get a full block on each character, which slowly fades to nothing over 5-10 mins.

LCD smartie detects the LCD, and it can control the contrast and backlight, but I haven't been able to get any useful display, or a noticeable reaction when changing the screen to be displayed in LCD Smartie.

My soldering isn't fantastic, but I can't see any shorts, and since the LCD hasn't exploded, the wiring can't be far wrong.

Any suggestions on where to look first?

Thanks!

[hydrolisk1792]

I understad that you can control the contrast and brightness, however for it to load up the blocks (common when using the HD44780 driver LCD module in the startup) however for them to fade over time, that seems to be a defective display, or you have some wiring crossed. Make sure that you didn't accidently hook a power pin to a data pin as well as to the power for the display. These displays are tipically ran @ 5VDC which you should be able to pull from the backpack board. . . Literally, double check the wiring and make sure that everything is wired correctly, if that is so, then you may have a defective LCD module.