Uart Interrupt priority for BLE Mesh with PWM (Dimmer Example)

[bivay]

Hi,

When I reference of SDK Coexist examp of uart for adding in Experimental dimming example.

I get success in it. 

I take dimming level from uart, and publish it via client.

Then mesh Asserts happens.

After some search I learn that I have to use interrupt priority level to APP_IRQ_PRIORITY_LOW 

instead of "APP_IRQ_PRIORITY_LOWEST".

And mesh assert problem is solved.

But when I added pwm in Dimmer client example for own dimmer refrence from server example.

Dimming is also working.

But When I use uart combined with pwm then problem rises.

NRF52832 gona reset when pwm level is above 50%.

Then I changed Uart interrupt priority to "APP_IRQ_PRIORITY_LOWEST" then pwm works without Hang or reset with wdt.

So problem is

if I use APP_IRQ_PRIORITY_LOWEST I can use PWM but not Uart

and

if I use APP_IRQ_PRIORITY_LOW I can use Uart but not PWM.

Please help me regarding it.

Thank You

Bivay

[Mttrinh]

Hi,

Which Mesh SDK version are using?

[bivay]

Mesh SDK:3.2.0

[Mttrinh]

But when I added pwm in Dimmer client example for own dimmer refrence from server example.

Do you have dimming server also present on the same node? Are you trying to send a dimming client message to its own server instance?

What is the mesh stack priority?

[bivay]

Mesh stack priority is NRF_MESH_IRQ_PRIORITY_LOWEST means 6.

Dimming server and uart in one device and

Dimming client and uart in other device.

[Mttrinh]

Hi,

Can you check if you inadvertently causing an IRQ lock within mesh IRQ context or in UART context (e.g. : Triggering UART TX/RX from inside of the dimming client/server callbacks that execute in Mesh IRQ context, and/or triggering Mesh APIs from inside of the UART callbacks/irqs. ). Such interlocking call can give rise to either dimming functionality getting stuck or UART one.

To avoid this, a user can run the mesh stack in thread mode using the app_scheduler (see: https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.meshsdk.v3.2.0/md_doc_introduction_mesh_interrupt_priorities.html?cp=5_2_0_4), or if that is not possible, create some mechanism to introduce context separation between UART and Mesh API calls.