Permanent Storage

Device Code
1

I’m looking for somewhere to store settings over a power cycle when the device is offline. I read this in the documentation:

“A typical use for permanent storage is to cache a device’s settings so that they are retained even if the power should fail or the gadget be restarted for some other reason. The device’s developer might well incorporate a small flash memory chip and write the data there, but the Electric Imp Cloud’s permanent storage facility offers a considerably less expensive alternative – though it requires Internet access, of course.”

Is this still the case with 003? I’m trying to see if there is anywhere else we can store a simple table on the device without adding a flash memory chip to the board.

Thanks

2

With '003 you have to add a flash memory chip to the board anyway for the imp’s own purposes, but the imp only needs ~1.5Mbytes, and the chips come in powers of two, so there’s at least 400K or so available to the user even if you fit a 2Mbyte chip, the smallest suitable size: see hardware.spiflash().

Peter

3

Great thanks very much

4

Wait, I got the numbers all wrong. You need to fit at least a 512Kbyte flash, and the imp uses 448K for its own purposes, so there’s perhaps as little as 64K for the user. But you get the general idea!

Peter

5

As noted in the docs, you can also oversize the SPI flash if you need more than 64K.