Pages: [1]   Go Down
Author Topic: Need to hook-up AREF on standalone project ?  (Read 535 times)
0 Members and 1 Guest are viewing this topic.
Denmark
Offline Offline
Newbie
*
Karma: 0
Posts: 6
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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.
Logged

Global Moderator
Offline Offline
Brattain Member
*****
Karma: 485
Posts: 18771
Lua rocks!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

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


Australia
Offline Offline
Sr. Member
****
Karma: 13
Posts: 446
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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.
« Last Edit: April 16, 2012, 07:17:04 pm by lemming » Logged

Denmark
Offline Offline
Newbie
*
Karma: 0
Posts: 6
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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 smiley. 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!
 
Logged

Denmark
Offline Offline
Newbie
*
Karma: 0
Posts: 6
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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



And the finished project with BL control:




Again, thanks for the help!
Logged

Pages: [1]   Go Up
Jump to: