Does SoftDevice S112 or S113 offer mesh support on a nRF52811?

[LarsH]

Does SoftDevice S112 or S113 offer mesh support on a nRF52811?

The intended use is for an end-device running very simple app-logic. According to the SoftDevice properties in "s112_nrf52_7.0.1_release-notes.pdf" the combined MBR and SoftDevice memory requirements are 100.0 kB flash and 3.7 kB RAM. That leaves about 24 kb so it ought to be doable if the application fits within that space, isn't it? 

What I also couldn't figure out, is if the mesh functionality affects the call stack heavily. The release notes states that the worst-case stack usage is 1.5 kB but that seems a bit low.

Btw, what's basic difference between S112 and S113? I couldn't find any comparison charts regarding this.

[Simonr]

Hi

I noticed that it isn't mentioned in the compatibility section of the nRF5 SDK for Mesh v.4.0.0 on the Infocenter, which I have reported this internally. However, both S112 and S113 should be compatible with the nRF52811, and the nRF52811 should have limited Mesh support for the same reasons as the nRF52810. This is due to the platform being very limited in RAM and Flash Memory, and therefore doesn't support DFU and logging. The nRF52811 must also be compiled with optimization for size, which is described in the compatibility section of the Mesh SDK on the Infocenter.

The main difference between S112 and S113 is that S113 supports LE Data Packet Length Extension.

Best regards,

Simon

[LarsH]

Regarding the Mesh support, can you please be a bit more specific about the limitations of the nRF52811?  

The compatibility section of the Mesh SDK on the Infocenter doesn't give you very much information regarding what specifically will work or not regarding the BlueTooth Mesh implementation. Also, nRF52811 isn't mentioned as well. 

Are there any other documents or guides that provide more detailed information with possible workarounds?

I'm specifically interested in using the the Low-Power Mode feature as the end-device will be in low-power sleep state most of the time (after been provisioned to the network of course)

Thanks, Lars.

[Simonr]

Hi Lars

The only limitations should be the limited RAM and Flash memory in this chip, which results in no support for DFU and logging (these are the main features that will be missing). The RAM and Flash memory will also restrict the maximum size of your application, as you can't have very large applications on the nRF52811.

As mentioned in the compatibility notes, the Low Power node example is not supported on the nRF52810 (and therefore not on the nRF52811 either). This is because the example includes the Buttonless Secure DFU Service to perform DFU over BLE as well as logging. So to be able to make a low-power node application for the nRF52811 you will have to disable/remove both of these features from the example project, and make sure that it is compatible in terms of size with the nRF52811.

As for documentation regarding the Mesh SDK, it should be covered on the Infocenter, but we also have some Mesh guides here on the Devzone as well.

Best regards,

Simon

[LarsH]

Hi!

Just to sum up so I did not misunderstand: It's just the example application itself ("Low Power node example") that cannot fit because of the size but otherwise there are no restrictions in the respective SoftDevice besides DFU, logging and size of ram and flash for the nRF52811?

What about the worst-case scenario with 1.5 kB usage for the call stack, is this still the case as stated in the release notes? Does that in include link and connection state information as well? It would be really useful if there was some kind of estimate for connection state sizing so on.
--

Thanks Lars.

[Simonr]

Hi Lars

Where do you see that the usage for the call stack is 1.5kB? According to the resource usage page (specifically RAM and Flash usage) in the nRF5 SDK for Mesh v.4.0.0, the mesh stack requires a minimum call stack size of 2kB. I think you can find a lot of useful information regarding the resource usage of the mesh stack there.

Best regards,

Simon