Go Down

Topic: Need to hook-up AREF on standalone project ? (Read 589 times) previous topic - next topic

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.

Nick Gammon

AVCC (20) to +5V.
AREF (21) not connected but you might put a 0.1 uF to Gnd.
AGND (22) to Gnd.
Please post technical questions on the forum, not by personal message. Thanks!

More info:
http://www.gammon.com.au/electronics

lemming

#2
Apr 17, 2012, 02:14 am Last Edit: Apr 17, 2012, 02:17 am by lemming Reason: 1
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.


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.



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



Thats great, thaks!

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



And the finished project with BL control:




Again, thanks for the help!

Go Up