I want to create my own board for the imp001.
I see no mention on the imp web site that says it needs the ATSHA204-TSU-T ID chip.
Yet all the break outboards have them. Digi-Key and mouser show them out of stock and obsolete.
What is the replacement for them, and why is this part not described or talked about on your page here:
https://electricimp.com/docs/hardware/resources/reference-designs/april/