SparkFun Forums

[thefatmoop]

Are there any schematics / guides on how to wire up an arduino's atmega168 chip? I have some projects that i want to make permanent and solder them to some pcbs

http://hcgilje.wordpress.com/resources/ ... tandalone/

something like that are there guides that show how to do it with a resonator, and a crystal?

[signal7]

The datash33t should have the basics. The schematics for the crystal and the other features of the chip are broken up into their individual sections so you might have to hunt for the relevant pieces, but they should be in there.

One alternative way to go about this would be to start with the schematic for the arduino and then adapt it to your specific project. That's the beauty of open hardware - everything that went into it is available online. Here is the "I'm feeling lucky..." link from google: http://www.arduino.cc/en/uploads/Main/A ... ematic.pdf

[metsfan]

I spent some time figuring out the same thing working on my first (and current) project. At some point, I plan to do a writeup explaining how to move from the dev board to a more permanent project. For now, here's a schematic running on a 16MHz crystal.



Click: http://flickr.com/photos/penner42/3153679479/ and then All Sizes to see it bigger.

The ISP header is for programming the chip once it's off the Arduino board. It's not absolutely necessary, but I've found that I didn't finish the software completely, and it's easier to program that way than to keep moving the chip back to the Arduino. You need a programmer, I use a USBtinyISP: http://www.ladyada.net/make/usbtinyisp/

If you don't need to program it, and don't need the reset switch, you can just tie the reset pin high instead of using a pull-up resistor.

[signal7]

It's not recommended, but I've left the reset line to float on numerous AVR's and never had a problem. I'd be surprised if there isn't an internal weak pull up on that pin.

[leon_heller]

I'd make it an output if it wasn't connected. It could pick up noise, otherwise, causing random resets.

Leon