Difference b/w Vcc and AVcc

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I am using STK500 , mega16 and I am confused with the pins Vcc and AVcc. When I checked for the continuity (at pins 10 and 30) they are connected/short. Then whats the difference.

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anmol2701 :

Quote:
VCC Digital supply voltage.

AVCC AVCC is the supply voltage pin for Port A and the A/D converter. It should be externally connected to VCC, even if the ADC is not used. If the ADC is used, it should be connected to VCC through a low-pass filter.

ATMEL AVR ATMega 16 / 16L : Document 2466N–AVR–10/06


I think that should answer your question.
India_AVR

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I am using STK500. Now, queries are:-

1) Even with this one I have to establish the connections externally when using ADC.

2) Vref - reference voltage. Assuming that my reference voltage is 5 volts. How can I establish connection ie. from where to get 5 Volts.

3) What is this VTARGET and AREF jumpers used on STK500 kit. Actually , I was going through the User Guide of STK500 but I am unable to catch the point.

Thanks,

Anmol Kumar

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Please see data sheet ATMega16 "doc2466.pdf" from :-http://www.atmel.com/dyn/products/datasheets.asp?family_id=607
for relevant points. The nomenclature used for STK500 if in variance could be easily corelated. Sorry I do not have STK500 to give direct reply.

India_AVR

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Thats what I am confused with the different nomenclature.So, Waiting for reply from someone who knows or using STK500.

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Studio4 -> Help -> STK500 Manual

You can read the STK500 schematic from here. And see for yourself.

AVcc is normally just the same as Vcc with some extra smoothing.

Aref is set to what you require. The STK500 can alter this. In practice you either use the voltage at this pin as an external reference or you use an internal fixed voltage ref.

David.

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Quote:
Vref - reference voltage. Assuming that my reference voltage is 5 volts. How can I establish connection ie. from where to get 5 Volts.

please try to understand my question.

Quote:
Aref is set to what you require. The STK500 can alter this.

How can I set this value or altering through STK500.

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Via Studio4 -> Programmer -> STK500 -> HW Settings

You can set Vtarget and Aref.

Alternatively you just issue the appropriate commands to stk500.exe via the command line.

David.

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Via

Quote:
Studio4 -> Programmer -> STK500 -> HW Settings

unable to find the link

Quote:

Alternatively you just issue the appropriate commands to stk500.exe via the command line.

if you please explain me more this one.

Thanks,

Anmol Kumar

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Studio4 -> Tools -> Program AVR -> Auto Connect

or

Studio4 -> Programmer ...

where Programmer is the little black caterpillar icon. A Black rectangle that looks like a AVR chip.

Do you know what a command line is ?

If you do, you type "stk500.exe" or "stk500 -h" and you will get instructions.

David.

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found the first link actually my STK500 was not powered up.

Command Line up to my knowledge these are used to pass some commands (in text based or line based). But the question arises here where to type these commands. Are you talking about linux platform (where we can type the commands through terminal)

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No. You can use CMD.EXE in Windows. (It is worth changing the default size and colours.)

You can then operate all the gcc tools fairly painlessly. You can even use bash. You are still limited to Windows brain-death but most simple things work.

Operating stk500.exe from the command line is very handy to test routine operations. Check the syntax, and then add to your makefile, batch file or shell script.

David.

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Hi SteveN,

I checked the continuity while Mega16 was sitting in the IC Base. So, according to you it should be short.

You are totally understanding my question. Thanks for clearing the confusion.

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Hello David,

I found it thanks for letting me know this hidden concept for me.

What do you mean by this one..

Quote:

Check the syntax, and then add to your makefile, batch file or shell script.

Is there any link from where I can found more about this command based firing.