Hello.
I'm looking at options for a BLE device that has fairly small application requirements. It would essentially be a button, so the peripheral blinky example would make a great starting point. I do have some other requirements as well, but for now my main question is about the ability to update the device.
I'm a bit reluctant to specify a device that can't be fully updated. So I'm mainly looking at the 52820 now, as the smaller ones clearly can't update the softdevice. But is that feasible even for the 52820?
Looking at the memory assignments of the example projects in nRF5 SDK v17.1 I see that the BLE secure bootloader is placed at 0x38000. And the S112 softdevice occupies space up to 0x19000. That leaves 0x1F000 of free space. The size of the bootloader is set to 0x6000 in the example project, so the size of a BL+SD update would be exactly 0x1F000.
So if I got the above right, a full update would just barely be possible for the 52820. However if the application requires any nonvolatile storage (ie FDS), then there would no longer be enough free space for a BL+SD update.
So my questions are: Is my reasoning above correct? Can I fully update an nRF52820 over BLE? Or are the 52833 and 52840 my only options?
