Hi,

I've been working on my first PIC project, I can switch led's on and off etc.

So, I got an HD77480 LCD to play with, I can get it initialised and get the cursor to be displayed and move around the screen.

The only problem I seem to have at the minute is that no matter what text I try to write to it, nothing is displayed...

I've attached the source code and a picture of what you can see on the LCD.

The illuminated block is the blinking cursor...

Any idea's what I'm doing wrong?

Cheers,
Blakey

 

FYI the picture of the LCD is upside down

 

Have you done some debugging in MPLAB SIM?

 

Nope, My code seems to work - the lines are going high when I set them high.

The only difference between the commands and text writing routine is the RS line - which is behaving correctly.

I'll have a look for some info on debugging later

Cheers,
Craig

 

Hi,

Looks like the code was correct and the wiring was correct between the chip and the LCD module.

I connected a common anode RGB led via a transistor to the enable line and the display now works, this leads me to suspect I need a pull down resistor...

Does anyone know how I go about figuring out what resistance I'll need here?

Cheers,
Craig

 

Hi,

Looks like the code was correct and the wiring was correct between the chip and the LCD module.

I connected a common anode RGB led via a transistor to the enable line and the display now works, this leads me to suspect I need a pull down resistor...

Does anyone know how I go about figuring out what resistance I'll need here?

Cheers,
Craig

It is a LCD example in the C:\Program Files\HI-TECH Software\PICC\9.81\samples folder. Take a look at that. It may give you some ideas

 

if the wire and programming are correct.. just one question, is a 14 pin LCD or a 16 pin LCD??.. because if is a 16pin.. you have to connect a variable resistor to regulate the backlight..

sometimes i have that problem in somes LCD ..

GL