Check it once more 
There is this one course project we were doing. Since we specified the board quite small, so we decided to order the board from a manufacturer, since we found one cheap enough for our budget. We waited for 3 weeks for the boards to arrive. It was then 3 weeks before the deadline.

We happily went to reflow lab to solder the components. everything seemed fine and cool first, until we found out several components had footprints of wrong size. There had been some mistakes when making the footprints, particularly someone misunderstanding MSOP8 for SOP8 and reversing battery holder's pins. That was still doable, few jump wires, problem solved. But there was something more...

I had found a library of avr 32-bit chips, symbols correct, footprint seems legit, alright, let's use this! is what I thought at that time. However, after using 10 hours to hack 40+ jump wires of width 0.2 mm, length less than 1 cm connect a 64-pin TQFP packaged chip on the board, I was cursing my stupidness.

The package was TQFP 64 alright. Just that it was smaller than any other TQPF 64 package I had seen before. And, oh yes, checking the datasheet told me it was indeed TQFP 64 and some letter combination I had not seen before. Checking further, I found the footprint on the datasheet, clearly showing the rigth size. Apparently the library I had used was outdated.


After 10 long hours, this resulted.

Okay, I guess everyone got the lesson. Always check the footprints, no matter how proper the libraries seem. Plan your schedule so that you have time for mistakes. Double check footprints. You'll save time doing that. There were some benefits in this too though. I learned how to solder damn small pins for instance. And everyone seeing the jump wires was like wow, how the hell did you manage to solder that? And of course, my patience got considerable boost enduring those 10 hours, resoldering after accidentally removing few of the wires I just had soldered.

That's all, happy checking, everyone!

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