AVCC & AGND connection during ISP?

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#1
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Hallo AVRFreaks,

I'm working to get one. But first I have a Question.

I'm just developing an ISP-Programmer for all AVR-Typs with only one Textool-Socket. If I will programm an 8535 or 2333 there are the Pins for analogpart (AVCC, AGND and AREF). Can they float during ISP-Programming or must I connect them to VCC GND and UREF to ??

The boardlayout will be easyer with floating!

Thanks fpr your interrest

Peter
DD8HS

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For programming you do not need connect AVCC, AGND, AREF
Those connection only for ADC convertor or AD comparator.
You can connect AVCC to VCC and AGND to GND, AREF- float.

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Hi,

Note that AVcc feed the PORT A output drivers! So connect AVcc if you want to use Port A.

Never leave pins floating if you want to minimize the supply current....I would recomment AGND to GND and AREF to Vcc.

Regards,
Jacob Lassen
Field Applications Engineer, AVR products, Atmel

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