@NeverDie I love the Feather boards. Currently working with the RFM69 feather. Build in battery connector/charger is very nice to have.
Have you found a cheaper source than Amazon for buying them?
where it's just every pin of the SAMD21 mapped to a post, and it's only just the SAMD21 chip on the board. Then I can experiment on breadboard and figure out what I want and what works before finally reducing it to a subsequent PCB.