Author Topic: 100pin ATmega boards with power bus?  (Read 2415 times)

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Offline AdminTopic starter

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100pin ATmega boards with power bus?
« on: September 18, 2007, 08:58:44 AM »
Ive been looking around for a board that uses one of the 100 pin ATmegas, such as the ATmega1280/ATmega2560/ATmega640. Im tired of never having enough UART or digi output pins or ADC or timers . . .

Ive found a bunch, but I dont like their breakout because its not next to a power bus - so that I may easily plug in a servo or rangefinder!

Anyone seen some that I could buy?

More as a reference to myself, these are the boards Ive been able to find, but no power bus :-\
http://www.mikroe.com/en/tools/mcu_cards/avr/bigavr/
http://www.siphec.com/item/ATm1280-UT-TB.html

Also found this, which comes with a possibly modifiable schematic and gerber files - if I really want to go through the trouble of making my own boards . . .
http://www.noplabs.com/atmega2560breakout/atmega2560breakout.html

Offline sdk32285

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Re: 100pin ATmega boards with power bus?
« Reply #1 on: September 18, 2007, 09:18:30 AM »
I know its convenient but its usually better not to put the power lines next to the I/O.
With the small signals being fed into the ADC they are very susceptible to noise and interference from the power lines.
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Re: 100pin ATmega boards with power bus?
« Reply #2 on: September 18, 2007, 12:57:44 PM »
That shouldnt really matter for 8 bit ADC. Voltages should be amplified before going in, and capacitors employed across the power bus to suppress signals, no?

I dont think noise will bother the typical robot . . .

Offline sdk32285

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Re: 100pin ATmega boards with power bus?
« Reply #3 on: September 18, 2007, 02:24:52 PM »
While it will probably work with no problems.
The amplified signal lines are probably at a lower voltage than the power lines ??
The capacitors will filter out any high frequency components (presumably most of the noise is high frequency)...

Also if something needs to be done for testing, quickly, or temporarily will it always be filtered and amplified.
« Last Edit: September 18, 2007, 08:43:39 PM by sdk32285 »
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Re: 100pin ATmega boards with power bus?
« Reply #4 on: September 18, 2007, 02:31:46 PM »
hmmmm well, for my application it wont be a problem.

Im playing around with Eagle CAD (Im totally a noob with it) to design my own board since I cant find one. Anyone know how to put headers in the schematic? :-\

Offline JesseWelling

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Re: 100pin ATmega boards with power bus?
« Reply #5 on: September 18, 2007, 05:34:55 PM »
aren't the a2d's on most avr's 10 bit? or are you only going to use 8 bit?

Offline Ro-Bot-X

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Re: 100pin ATmega boards with power bus?
« Reply #6 on: September 19, 2007, 12:48:12 AM »
To add headers on your schematic, click on Add button, search for con-hdrs40 library for molex headers or con-lsta for female headers and con-lstb for male pins.
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Offline TrickyNekro

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Re: 100pin ATmega boards with power bus?
« Reply #7 on: September 21, 2007, 11:44:12 AM »
To add pin headers simply search for "pin header"!!!
Click Add and then write "pin header"
Something that disturbed me was finding the phoenix connectors, just write "phoenix" (I didn't really know the traslation of the world in english, I'm Greek!!!)
Finally, if looking for PC connectors like the serial or parallel type "sub-d"... It made me very nervous looking for them!!! So if ya need any help... let me know!!! I had a very hard time learning it all alone... So I know how it is....

Regards, Lefteris
Greece
For whom the interrupts toll...


P.S. I've been inactive for almost a year... Don't give promises but I'll try to complete my tutorials. I'll let you know when..

Cheers!

 


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