### Author Topic: a2d on a 3v chip  (Read 1065 times)

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#### ed1380

• Supreme Robot
• Posts: 1,478
##### a2d on a 3v chip
« on: April 10, 2010, 10:28:32 PM »
The uc I'm using is the xmega64a3. http://www.atmel.com/dyn/resources/prod_documents/doc8068.pdf
It has a max input vcc of 3.3v. So is the a2d only 0 to 3.3v? would I need a voltage devider?

Thanks

BTW: nice to be back ^_^
hope admin feels proud cause I'm on the AUV(autonomous underwater vehicle) team at my university lol
« Last Edit: April 10, 2010, 10:32:19 PM by ed1380 »
Problems making the \$50 robot circuit board?

#### tim_wang

• Jr. Member
• Posts: 32
##### Re: a2d on a 3v chip
« Reply #1 on: April 11, 2010, 05:24:28 PM »
According to page 67 of http://www.atmel.com/dyn/resources/prod_documents/doc8068.pdf, maximum AREF = Vcc - 0.6V, and from page 63, maximum Vcc = 3.6V, so the maximum ADC input would be 3V.

• Supreme Robot
• Posts: 11,696
##### Re: a2d on a 3v chip
« Reply #2 on: April 29, 2010, 09:28:54 AM »
Yea, voltage divider. Use really large resistance resistors to avoid power waste.

BTW: nice to be back ^_^
hope admin feels proud cause I'm on the AUV(autonomous underwater vehicle) team at my university lol
Only proud if your team wins

(nice to see you back, been like 2 years?)

#### ed1380

• Supreme Robot
• Posts: 1,478
##### Re: a2d on a 3v chip
« Reply #3 on: April 29, 2010, 09:58:19 AM »
I put voltager dividers on the avcc and a2d ports to lower it to 3v. ironically the EE major is doing structure and ME is doing electronics

I think I asked a question few months ago but we dont stand a chance again subs costing 10x as much as ours taking a breather this year since about 80% of the team graduated.

Hows asia? Must be nice having cheap components at hand. takes me 3 weeks to get anything lol
Problems making the \$50 robot circuit board?

• Supreme Robot
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