IMP card and ATSHA

Device Code
1

I’d like to understand more fully how the ATSHA chip works. If I take a connected and programmed Imp card from an April and connect it to a circuit without an ATSHA chip, do I need to clear it and reconnect it? Will it show up as a new device?

Also, are there any recommended SD card sockets that are carried by Digikey, or is the 4UCON socket the best bet?

Also, is this the correct part? I can’t find 19646 on the 4ucon site… at least on the site where you can order parts.

http://www.4uconnector.com/online/object/4udrawing/19608.pdf

2

It won’t show up at all. The imp card needs the atsha to identify what it’s plugged into.

Suggested sockets and digikey PNs are here: http://devwiki.electricimp.com/doku.php?id=newimpee

Digikey also sell the ATSHA. You need this chip and a 100k pull up resistor.

3

So how does the imp002 operate? Does it have an internal atsha device?

4

Because the imp002 isn’t moveable device to device, it has a fixed internal ID. The ATSHA is needed as a small inexpensive way to uniquely identify a device using only one wire.

5

Ahhh. Now it all makes sense. Thanks!