7 years, 10 months ago.

ST7066 20x4 Display not working with the TextLCD Enhanced library

Hello everyone! It's my first post here, so I'm not that familiar with how stuff works here.

I'm doing my final thesis project for my studies and I've run into a problem.

Straight to the point anyways.

I have a Raystar 20x4 LCD: RC2004A-FHW-CSV (datasheet available here: http://www.raystar-optronics.com/down.php?ProID=39) and I'm using a NUCLEO-F446RE for my project. The display has a ST7066 controller, I've read that it's nearly a copy of HD44780, but it wasn't working with standard TextLCD library, so today I've changed it to the TextLCD_Enhanced but it still doesn't work even though I've initialized the display as one with such controller.

My connections are as follows: (commented in the code as well) Pins: 1 GND 2 5V on the Nucleo 3 10k potentiometer powered with 5V from the nucleo (as for now only) 4 (RS) D5 5 (R/W) GND 6 E D4 7-10 Not connected 11-14 D3-D0

Backlight is not used yet.

I just wanted to have the display working so I could progress with the main part of my code.

I've attached my whole code as a zip. /media/uploads/fili2554/chamber_nucleo-f446re_zip_nucleo_f446re.zip

Here's what I get in the end. No matter what is the contrast, I only get 2 lines "working" but they're not even displaying anything. /media/uploads/fili2554/wp_20160504_21_40_44_pro.jpg

Any help would be greatly appreciated, as my deadline is getting close way too fast.

It's already been solved, I've totally forgot about the solder bridges and that fact that some of the pins are by default used for debugging.

posted by Filip Zaręba 06 May 2016

1 Answer

7 years, 10 months ago.

The two dark lines are typical of a display that has power and contrast voltage but that has not (yet) been initialised. The ks0066 should be compatible with the default hd44780. Good that you found out that d0 and d1 are by default not connected on the nucleos. You can use any other free DigitalOut pin instead of d0 and d1.