ATmega644

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vitals817
Posts: 12
Joined: Mon Aug 25, 2008 7:04 am

ATmega644

Post by vitals817 »

Is there a specif ATmega644 or any
Because I saw a few versions of the ATmega644
ex ATmega644-20AU
Thanks
CompMan
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Location: Kent, WA

Re: ATmega644

Post by CompMan »

In order to insure the correct part you must look at your requirements. You know you need the ATMEGA644. You then need to look at the case type. Assuming you don't want to solder a surface mount part you should look at the DIP. Also look at the clock speed you will want one at 20 Mhz. You should find three parts that meet this requirement.

ATMEGA644-20PU, ATMEGA644P-20PU, ATMEGA644P-20PQ

The ATmega644P has overclocking problems so that leaves you with one choice the ATMEGA644-20PU.

I hope this helps,
CampMan
aphixe
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Joined: Mon Aug 25, 2008 9:24 pm

Re: ATmega644

Post by aphixe »

wheres the cheapest place to buy it?
vitals817
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Re: ATmega644

Post by vitals817 »

Thanks for the help
also what type of programmer do I need
or does this have one built in to this project
what is the isp port for
Thanks matt
CompMan
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Location: Kent, WA

Re: ATmega644

Post by CompMan »

aphixe - I don't know where the cheapest price is but when you look at shipping costs you would be better off getting all the parts from one place. I would recommend Digi-Key. You could also try to request a free sample from Atmel.

vitals817 - The ISP port is where you plug in the programmer. The cheapest thing to do is build a programmer or you could buy one from any AVR supplier. Digi-Key also sells one. Something like the ATAVRISP2-ND would do the job for a USB based programmer.

CampMan
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uze6666
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Re: ATmega644

Post by uze6666 »

I highly recommend Digi-Key, I buy all my stuff from there. All duty and brokerage fees are included in the catalog prices, so thats a blessing if you are living outside the US.

To program AVRs, the cheapest way I know of is the Atmel ATAVRISP2 (as CompMan mentionned).

You can get it at Digikey for ~36$US: http://search.digikey.com/scripts/DkSea ... AVRISP2-ND
aphixe
Posts: 6
Joined: Mon Aug 25, 2008 9:24 pm

Re: ATmega644

Post by aphixe »

I didnt mean to program it, I meant the chip. but I look for it there. right now I'm making a list of all the parts I can find on digi-key..
milo_00
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Joined: Thu Aug 28, 2008 3:02 pm

Re: ATmega644

Post by milo_00 »

Hi,

Does this mean that you have to use a 664 or can i substitute it for a mega 32 or even a 128??

cheers

milo_00
CompMan
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Location: Kent, WA

Re: ATmega644

Post by CompMan »

milo_00 wrote:Does this mean that you have to use a 664 or can i substitute it for a mega 32 or even a 128??
You should use the 644.

Cheers,

Compman
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uze6666
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Re: ATmega644

Post by uze6666 »

You should use the 644.
In fact, you must. The ATmega644 is, as far as I know, the only one with decent memory (>2K RAM) in a DIP package. And more importantly,its rated at 20Mhz to reliably overclock. The mega32 and 128 are 16Mhz devices.
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