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Topic: pulling out atmega chip (Read 885 times) previous topic - next topic

treebykooba

Jun 15, 2011, 06:09 pm Last Edit: Jun 15, 2011, 06:16 pm by treebykooba Reason: 1
Hello,
To make a project more permanent...could one pull out the atmega chip from the arduino (the older ones anyway) and solder it onto a perf board? Would it be as simple as grounding it and powering it and then connecting whatever sensors you have to its pins? would that work? could I buy a bunch of these to use? http://www.mouser.com/search/ProductDetail.aspx?qs=K8BHR703ZXguOQv3sKbWcg%3D%3D
My problem is that when I make things they need to be moved around or shipped and the wires always fall out of the pins...but also sometimes I just use a few pins. It would be nice to buy 4 dollar atmega chips and not $30 arduinos every time. could one use the arduino board as a programmer like that?
thanks for any feedback!

Coding Badly

#1
Jun 15, 2011, 06:29 pm Last Edit: Jun 15, 2011, 06:31 pm by Coding Badly Reason: 1
Hello,


Hello.

Quote
To make a project more permanent...could one pull out the atmega chip from the arduino (the older ones anyway) and solder it onto a perf board?


Yes.

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Would it be as simple as grounding it and powering it and then connecting whatever sensors you have to its pins?


No.  You will also need a 16 MHz crystal oscillator and a pair of capacitors.  OR, a 16 MHz resonator.  OR, you can change the fuse settings and use the internal 8 MHz oscillator.

If you are using the analog-to-digital converter you may need a few more components.

And, it's a good idea to include an external pull-up resistor (usually 10K) on the RESET pin.


There are some alternatives to consider...
http://arduino.cc/en/Main/ArduinoBoardMini
http://arduino.cc/en/Main/ArduinoBoardProMini

Or maybe something like this...
http://shop.moderndevice.com/products/rbbb-kit

Or my personal favourite...
http://www.pjrc.com/teensy/

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would that work?


Once you work out how you will clock the processor, yes.

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could I buy a bunch of these to use? http://www.mouser.com/search/ProductDetail.aspx?qs=K8BHR703ZXguOQv3sKbWcg%3D%3D


Stock: 45,671 Can Ship Immediately ... Yowsers!  I wonder how long those will last?

Sorry, got a bit sidetracked.  Yes, those are the correct part.

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could one use the arduino board as a programmer like that?


Yes.  

OR, the Arduino can be used as a programmer like this (search for "Circuit (targeting an AVR on a breadboard)")...
http://arduino.cc/en/Tutorial/ArduinoISP

cr0sh

More or less - you need to remember to add decoupling caps near the chip from the power supply, plus the crystal/caps or resonator (16 MHz). I would also purchase a 28 pin DIP socket for the chip (in case you need to replace it - much easier than desoldering). Also - you might want to extend out and put a header for the ICSP pins and/or the tx/rx pins (to attach an FTDI cable), for "field reprogramming").

Note that you shouldn't constantly pull and replace the chip in sockets - the sockets nor the pins on the chip are designed for it; if you expect to do this often, then you should invest in ZIF (zero insertion force) sockets (for both the Ardunio and your other board(s))...
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

treebykooba

#3
Jun 15, 2011, 06:57 pm Last Edit: Jun 15, 2011, 07:01 pm by treebykooba Reason: 1
thanks so much for your help! super helpful!
so I would basically hook it up like in this picture? http://arduino.cc/en/uploads/Tutorial/BreadboardAVR.png
flash a bootloader, program it, take out the wires connecting to the arduino, and then i could solder everything together?

for the 16Mhz oscillator...is this the correct part?
http://www.mouser.com/ProductDetail/ABRACON/ACH-16000MHZ-EK/?qs=sGAEpiMZZMtgSs4ktXb8phCkgIMQu9Wt
and the capacitors...those are .22uf, correct? does the voltage matter on the caps?
http://www.mouser.com/ProductDetail/AVX/TAP224K035SRW/?qs=sGAEpiMZZMukgiigmf73gMK3fcloEmA3

for the pull up resistor...that would be a resistor going from RESET to Vcc? As shown in the picture above, correct?

or...if i have a super minimal program...like...10 lines of code...would it be so bad to have the arduino use it's 8Mhz clock? then i wouldn't need any additional parts, right?

Thanks again!

Grumpy_Mike

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for the pull up resistor...that would be a resistor going from RESET to Vcc?

Yes

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and the capacitors...those are .22uf, correct?

No you need 22pF those are 220,000pF only 10000 time too big.

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would it be so bad to have the arduino use it's 8Mhz clock?

Problem is that then the boot loader would not work and the timers run slow. It is possible to do this but it is more complex. If you do however you can use the pins as extra input / output pins.

Kariky

How about that kind of connection (Does it really work ?  :P )

http://interface.khm.de/index.php/lab/experiments/sleep_watchdog_battery/
My software has no bugs, only random features.

Schmidtn

I've wanted to program chips and then take them out of the Arduino too.  This has been a great topic, but I still have one question.

Would you need a voltage regulator to run it off of a 9v battery?  Or is that what the caps are for?

retrolefty

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Would you need a voltage regulator to run it off of a 9v battery?  Or is that what the caps are for?


Yes, a voltage regulator would be required. The atmega chip has a 5.5vdc absolute maximum rating before damage. By the way those small 9vdc batteries are usually a very poor choice for most arduino projects as they have very limited current flow (current needed by all components used in the project) and small total capacity (battery life), and are quite expensive for the amount of total energy they supply. Four series wired AA recharable nimh or nicad cells are a better choice and can power the atmega directly without requiring a voltage regulator.

Lefty

Schmidtn

Thank you Lefty, I've wondered that for a year now, but never thought to ask.  I always used a 9v battery because my Arduino came with a little 9v battery holder, so I figured it was what everyone was using.  It does make way more sense to use rechargeables though.

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