LCD is not showing any text

Question

I'm using LCD QC1602A with a 10k potentiometer and changing contrast. It works well but the problem is that no text is appearing.

I'm using the LCD hello world examples and a few other examples. I tried reconnecting wires at least 5 times but every time it's the same problem. I connected it like this but the screen is not displaying any text at any contrast.

PS: It was showing white squares only in the top row, and now it's in both rows.

Answer 1

Two rows of white squares means that the driver chip has been successfully initialised to run in a 2x16 mode (it defaults to 1x16 which was the 1 row of squares you had originally).

So that means that you are configuring the display at least partially correctly.

You should adjust the pot so that you can just about see the squares. The squares are the background and the text would appear over them. If they are too bright you won't see the text. So adjust the contrast until you can just see that there are squares there.

If the wiring is correct and the code is correct then you should be able to see the text.

Answer 2

It works well but the problem is that no text is appearing.

it works well and yet no text is appearing?

so there is or there isn't a problem?

PS: It was showing white squares only in the top row, and now it's in both rows.

when correctly initialized, it should one row of blocks in the first row.

if it shows two rows of blocks, either it is not correctly initialized or the contrast is too much.

• Majenko: Actually, correctly initialised is 2 rows of blocks (it's set it up to be a 2 row display) and 1 row is not initialised (it defaults to a 1 row display). Two rows of blocks usually means the contrast is too high but communication is (at least to a certain extent) working.