I am back again with my (hopefully) completed project. I have just learned how to use EAGLE, so any advice is appreciated.
What I have made is a very simple breakout board for the ATtiny family of microcontrollers. It is supposed to be like the arduino, but much smaller (5 GPIO). I have included many of the things on the regular board minus USB as programming is done over ICSP. I have also made everything through-hole as I am not yet very good at SMD soldering.
I have attached the images of the board and schematic, if anyone is interested in seeing the eagle files themselves I can attach them, too.
If you look on the schematic, the voltage reg's cap technically acts as a decoupling cap. Another one would just be redundant.
It's too far away. Decoupling caps are only useful when the path that electrons travel [cap-->ATtiny-->back to cap] is as short as possible. The extra inductance in the traces due to the distance of the cap to the ATtiny makes C2 not effective for the ATtiny (though it is effective for the regulator).
There is a 95.32% chance it will work just fine as it is. But for me, given the cost of a cap I would put it on there anyways.
Do you think anything is too close (wires, vias, etc.)?
I think it looks fine, but it doesn't matter what I think. It matters what your PCB manufacturer requires! You have to run a DRC on your board and set the parameters appropriately for the board manufacturer.
I'll run a DRC, though, and add a cap. I'll post the new version maybe (V1.2)
I also decided to fix the Analog inputs, now they actually go in order. (that was v1.1)
The Dimension errors are telling you you have copper (pads in your case) too close to the edge of the board. Either move the pads away or change the Copper/Dimension clearance in the DRC settings to something smaller (if it's OK with your board house).
The Drill Distance error suggests you have a via on top of a pad. Try ripping up that trace and re-routing it, avoiding a via over the pad.
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The Rugged Motor Driver: two H-bridges, more power than an L298, fully protected
and BTW just plugged in my wall wart and my dc barrel jack, and the innermost pin is GND, outer pin is +V and the side pin is plug status. It's exactly how it is on the schematic. And also the tutorial I took on eagle said that this particular part was marked backwards on the schematic.
The middle pin (on the bottom of a DC jack) connects to the outside of the DC plug and the end pin, the center (positive).
His DC jack is connected correctly.
The routing doesn't look too bad but you should go with slightly thicker tracks if you can (no reason to go with tiny thin ones) and there are a number of other things I'd change slightly.
Try to make everything as even as possible, don't use 90deg angles (it's not good practice if you ever etch your own boards and it just looks bad), flood a ground plane (not hatched even though everyone thinks it looks cool).
Basically, if it looks neat it's probably better. Things like that track from your reset button to the 10K resistor make me cringe
The circuit and board are correct only if "the innermost pin is GND".
The innermost pin on the bottom of the DC socket not the innermost pin on the plug. I do agree that the schematic is technically drawn wrong (Well I think the connections on it are off...)
Ok... I'm working on everyone's suggestions... but I have a problem. If I place a via somewhere, I can't erase it. How do I do it?
Why do you need to place a via? It does it automatically. Opens up EAGLE
I presume you have your components connected together with airwires and then you're using the route manually tool rather than simply drawing tracks.
When I place a via (with the 'draw a via' tool) I can delete them easy enough (with the delete tool).
-If you can't do that - do you need specific layers turned on like you do for parts (tplace and bplace of you can't delete/move parts)
If you want to delete a via in the middle of a routed track then unroute each on each side and then delete the via.
When I was manually routing, I came across a need for a via. To insert vias, I just change the side (top or bottom) and eagle puts in a via. Then, later on, I realize that I don't actually need the via. I rip up the trace and re route it. But the via stays there, connected by an airwire. If I try to erase it:
Can't backannotate this operation.
Please do this in the schematic!
