08/15/2018 at 12:32 •
At this point only the formfactor and connectivity along with the usb-uart chip have been chosen.
This project is gona get done in Altium Designer 17.1 as I'm most comfortable with it.
Currently the project files are available in the github repository.
This is also where the pdf schematics and gerbers are going to be uploaded, when they get generated.
Release versions of the same will also be uploaded to hackaday.io for additional availability, but most current files will be on github.
I chose CP2102N-A01-GQFN20 for this project for 3 reasons:
1. It was the cheapest usb-uart chip on digikey, and it had 13680pcs in stock.
2. It is small, so less board area gets used and 3mm x 3mm QFN20 is still easy to solder with hot air.
3. It does not need an extra crystal, this results in saved board space and potential EMI/EMC benefits.
The other two projects where I plan on using this chip are more RFI/EMI sensitive than a simple usb-uart.
So doing this separately allows me to evaluate radiated and conducted emissions while also giving me a usefull tool.
If nothing else I'd suspect that having the silicon oscillator on die radiates far less than a crystal placed outside the case.
This is not a fancy project going for the wow-factor, this is just a small useful thing shared so that others might learn about my potential mistakes and maybe build their own.