Need to hook-up AREF on standalone project ?

Using Arduino Microcontrollers
1

I've allready got a little standalone control panel running, controlling six outputs and showing some txt in a 16X2 LCD. (based on Atmega 328 chip)
Now I come up with the idea of controlling the backlight in software, and i got a working program running on a UNO.
It controls the LED backligt with PWM pin 10.
Now when I inplement it in my stand alone project, do I then need to hook up the AREF pin to VCC and AREF GND pin to GND ?
Or is it just needed when reading anlog values ?

Thanks for the (hopefully) upcomming help and sorry if its a dumb question.

2

AVCC (20) to +5V.
AREF (21) not connected but you might put a 0.1 uF to Gnd.
AGND (22) to Gnd.

3

Aref does not need to be connected if you are not using the analogue inputs.

However do not use pins directly to run the backlight. Use a transistor in between as the backlights typically pull many times the current that a pin can handle.
I understand that the pins max out around 40 ma whereas with the LCDs that I use, their backlight pulls around 180 ma. This would burn out the pin and damage the 328.
Check your datasheets to be certain.

4

lemming:
Aref does not need to be connected if you are not using the analogue inputs.

However do not use pins directly to run the backlight. Use a transistor in between as the backlights typically pull many times the current that a pin can handle.
I understand that the pins max out around 40 ma whereas with the LCDs that I use, their backlight pulls around 180 ma. This would burn out the pin and damage the 328.
Check your datasheets to be certain.

Yes, I know, it would probably let out the magic smoke :). I will drive it using a Mosfet.

Thats great, thaks!

5

And here is the almost finished project, before BL control:

And the finished project with BL control:

Again, thanks for the help!