IAP and External flash

[jeff belz]

Posted on December 29, 2017 at 04:46

I have 2 questions -

Q1:

Can IAP be used to update the internal flash from an external flash.  Here is what I want to do:

   1) Download code to the External flash from a remote location.  Such as Wifi OTA

   2) Have code running looking for new image in the the external flash, notify the user to update by pressing a 

       a button or two and then have the IAP program the internal flash with the new image.

Q2:

When performing IAP do you need twice the flash as your program.  For example, if I have a program that is 32k, do I need 64k to do an IAP.  Thought being I'm storing the new program in a section of flash and the the IAP copies that code the program flash.    OR does it just overwrite the original program with the new one in the same flash location

[Tesla DeLorean]

Posted on December 31, 2017 at 14:14

You can use whatever memory you want to stage firmware updates. The code you write determines the functionality of your product.

[Tesla DeLorean]

Posted on December 31, 2017 at 15:04

The amount of memory needed depends on how small you can implement a boot loader that has the features you want/need to perform the update.

A loader that fits in 16KB can rewrite an application image of 1 or 2MB (less 16KB) without any additional memory. ie the loader can overwrite the application.