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

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

Simonr — Thu, 16 Jan 2020 09:38:59 GMT

I just got an update from the development team, and since the nRF52811 isn't mentioned in the Mesh compatibility section, it can not be considered to be officially supported (even limited), but that doesn't mean that it doesn't work. We just can't guarantee that it will work. Although I don't see why it shouldn't. I just wanted to mention that as a sort of disclaimer for you.

Best regards,

Simon

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

LarsH — Thu, 16 Jan 2020 09:28:04 GMT

Thank you, that sum things up!

BR, Lars.

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

Simonr — Thu, 16 Jan 2020 09:06:46 GMT

Hi Lars

What is it you need to add up? The overall stack size will depend on SoftDevice stack usage + Application stack usage. Seeing as the Mesh stack requires a minimum call stack size of 2kB, and the worst-case stack usage for the SoftDevice is 1.5kB (this will only occur in corner cases) this will make the total stack size ~3.5kB. You can modify the stack size in your project, as well as the Flash and RAM start/end addresses for your application.

Best regards,

Simon

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

LarsH — Wed, 15 Jan 2020 14:50:13 GMT

Thanks, that was exactly the kind of information I was looking for regarding resource sizing. I suppose you need to check the resource usage of all sub-systems to get a complete picture of the total need?

However, I was referring to the “call stack” info in the S112 SoftDevice Release Notes “s112_nrf52_7.0.1_release-notes.pdf” (s112_nrf52_7.0.1.zip) where it states “The worst-case stack usage for the SoftDevice is 1.5 kB (0x600 bytes)”. But as you pointed out, the resource usage page for Mesh v.4.0.0 states “requires a minimum call stack size of 2 kB”.

I must be missing som fundamentals because I can't get it together, can you please give me a hint how these things add up?

Thanks, Lars.

S112 SoftDevice properties (s112_nrf52_7.0.1)

This SoftDevice variant is compatible with nRF52805, nRF52810, nRF52811 and nRF52832.
This SoftDevice contains the Master Boot Record (MBR) version 2.4.1 (DRGN-10680).
- This MBR version is compatible with previous MBR versions.
The combined MBR and SoftDevice memory requirements for this version are as follows:
- Flash: 100.0 kB (0x19000 bytes)
- RAM: 3.7 kB (0xeb8 bytes). This is the minimum required memory. The actual requirements depend on the configuration chosen at sd_ble_enable() time.
- Call stack: The SoftDevice uses a call stack combined with the application. The worst-case stack usage for the SoftDevice is 1.5 kB (0x600 bytes). Application writers should ensure that enough stack space is reserved to cover the worst-case SoftDevice call stack usage combined with the worst-case application call stack usage.
The Firmware ID of this SoftDevice is 0x00CD.

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

Simonr — Wed, 15 Jan 2020 10:00:25 GMT

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

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

LarsH — Wed, 15 Jan 2020 07:57:50 GMT

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.

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

Simonr — Wed, 15 Jan 2020 07:02:04 GMT

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

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

LarsH — Tue, 14 Jan 2020 12:55:27 GMT

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.

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

Simonr — Tue, 14 Jan 2020 12:02:15 GMT

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