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Questions relating to designing PCBs
By jandirks
I am trying to design an adapter to make it possible to program Atmega8 in MLF-32 package in an Arduino (the Arduino uses Atmega8 dip 28 packages standard).

I am a noob with EagleCad, so I might be doing things wrong, but this is what I did.

- Put an Atmega8 dip28 on the schematic
- Put an Atmega8 MLF32 on the schematic
- connected all pins together in the schematic that are the same

Actually, I am not going to use an Atmega8 dip28, but I think I will be going to use 2 rows of 14 break-off pins. These will be placed at the underside of the board (and, of course, soldered at the top of the board). Can I expect to find solderpad at the bottom of the board, as well as on the top side of the board?

So far it was pretty easy. When I changed to the Board and moved the 2 components onto the print, I ran the DRC check. I was surprised to see that this check gave 'Clearance' errors between all the smd pad of the MLF32.

This is something I need to get solved before I can continue with this project.

I already played a little with the automatic routing. For now, I have not been able to get it over ~43%. I can do it manually, even from scratch, but testing showed that I will keep a lot of other 'Clearance' errors get when I do a DRC check, so I need to know:
- What settings can I change to avoid these errors in DRC check -> Clearance tab?
- What is the smallest size I can get the 'routes' to?

I hope someone can help!
By Lucien
Hi jandirks, I'm a noob at Eagle too, so I might not be the best help but....

The MLF32 package in the Default Eagle library has a space of less than 8 mil between pads, this is what generates the clearance error with the DRC. Perhaps you could look at this other thread for more info.

The default rules in Eagle are a line width of 10 mil and a clearance of 8 mil between objects. The BatchPCB rules allow for a line width of 8 mil, so you'd have to change the DRC rules to match this.
By jandirks
Thanks, let's see how it works out!
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