Problem with interfacing AVR ATmega324p with HD44780 LCD

[fmoraes]

Hi,

I am trying to get an LCD HD44780 LCD working with an ATmega324P. The LCD works fine in the self-test mode (pin 3 grounded) but I get nothing when trying to send data via the MCU.

I am using the lcd code sample that comes with avr-libc and 4-bit communication via port C.

Any suggestions of what might be wrong are appreciated.

Francisco

 

[Moof]

hd44780 avr

I think you should post your hardware connections and code for help.

or visit

this link. may be it will helpfull

http://www.avrfreaks.net/index.php?module=PNphpBB2&file=viewtopic&t=158&highlight=

 

[fmoraes]

hd44780 avr c

Well, I've tried some simple bit I/O on port C and it wasn't working. So I switched to port B and the LCD is working fine.

Any ideas of what I may have missed that could cause half of the AVR 324P to work and the other not?

Francisco

 

[Moof]

avr hd44780 pullup

Yes, i think you should disable Jtag.

 

[fmoraes]

hd44780+avr

Ok, I will give it a try. Is that documented somewhere that there could be problems with PORT C if it is left enabled?

 

[Moof]

help with avr hd44780

just check the datasheet carafully, you will see there that portC is for jtag. so if jtag is enable you can´t use every pin in portC.

 

[fmoraes]

chinese hd44780

I understand that, but the wording in the datasheet could have warned people about this common mistake.

I found several postings on the subject after your post of disabling JTAG, so I am not alone

Anyway, I will test it on the weekend again.

Thanks for the help.

 

[Moof]

avr hd44780 nothing

It´s common on every microcontroller. I started with pics, and happens to me that a port sharing with analog compartor, by dafault, was on, so when i try to use that port for output, i doesn´t work.

Cost me like an hour or more to realize why it didn´t work.

And of course, open collectors output, that you forget in the pcb, putting the pull up resistor to work. JAJAJA.


Now i use avr, i´m happier with avr. I stop developing with microchip like 2 years ago.