nRF52832: Disable executable RAM?

[charles]

We're using the nRF52832 and want to trap if various parts of RAM are ever executed. We'd like to restrict as much as possible. We run nRF SDK 14.0.0 and SD132v5.

Seeing that SoftDevice claims ownership of the MWU, what's the recommended way to trap when code runs in our application's RAM?

Thanks,

Charles

[tesc]

Hi,

In addition to the MWU, the ARM Cortex-M CPU in the nRF52832 is actually equipped with a Memory Protection Unit (MPU) module. We even have an MPU driver in the SDK, although you will have to look at the ARM Cortex-M MPU documentation for figuring out how to use it.

It is easy to get confused by terminology here, as for the nRF51 series in some situations we used the term MPU for the flash and peripheral protection used by the SoftDevice.

Regards,
Terje

[charles]

Oh, cool. And you can confirm that SoftDevice doesn't touch the MPU unit at all? It's ours to fully configure and use, at any time, without consideration for SD?

[tesc]

Hi,

Yes, I can confirm that the SoftDevice does not touch the MPU. (It only uses the MWU.)

I even found a Stack guard module in the latest SDK, which is used by the Experimental: Console over Bluetooth Application example. (I.e. that example uses both SoftDevice and MPU library.)

Regards,
Terje

[charles]

Thanks, this is great.