Hardfault with Zigbee initialisation when BLE SoftDevice is included.

[anusha_14]

Hello Nordic support,

I am working on an application that works either with BLE or Zigbee and the protocol to be used is determined at application startup. Initially, my application was only Zigbee based and was using RTOS for performing various operations. This is working as expected.

Now, I have added BLE support to this application and added the necessary macros. As mentioned in this link https://infocenter.nordicsemi.com/index.jsp?topic=%2Fsdk_tz_v4.2.0%2Fzigbee_multi_examples.html (point 6), I have initialised SoftDevice by calling the function  nrf_sdh_enable_request() in main.c and then call ZB_INIT() inside an RTOS task. However, while performing Zigbee initialisation, the program goes into hardfault. 

Could you please let me know what could be the possible issue here?

Regards,

Anusha

[anusha_14]

I found that the cause for the hardfault was the execution of xQueueReceive function provided with a timeout value. If I make this timeout as 0, there is no hardfault. However, the RTOS tick does not increment. Note that RTOS tick source is coming from Systick. If I do not call nrf_sdh_enable_request(), then the RTOC tick increments. Could you please provide possible reason as to why the RTOS tick count doesn't increase when I call nrf_sdh_enable_request()? 

[Susheel Nuguru]

I am not sure, never tested systick along with BLE myself. Maybe when you enable softdevice it disables systick and clocks RTC instead? Can you check if the internal Systick counters are ticking just to check if it is still being enabled and clocked after softdevice is enabled.

[anusha_14]

Hi Susheel,

I checked if the function xPortSysTickHandler  in  port_cmsis_systick.c which increments the tick count is called when softdevice is enabled. I noticed that this function is executed only if softdevice is not enabled.

[Susheel Nuguru]

Check if the SysTick_IRQn is still enabled after the softdevice is enabled? I have a feeling that maybe the systick interrupt is being disabled after the softdevice.. You can use NVIC_GetEnableIRQ API to querry if a particular irq is enabled or not. Check if the interrupt is still enabled after the softdevice is enabled. If you find it disabled, then enable it after the softdevice is enabled. I have a feeling that softdevice might be disabling systick irq when it is initializing.

[anusha_14]

Hi Susheel,

Thanks for your response. However, it looks like I cannot use NVIC_GetEnableIRQ  to check systick interrrupt is enabled or disabled as it cannot be used with negative interrupt numbers. Systick interrupt has a value of -1. 

This seems to be also mentioned here:  NVIC check if IRQ is enabled 

I have also read that instructions WFE/WFI will also cause systick timer to stop. Ref: https://devzone.nordicsemi.com/f/nordic-q-a/76759/wfi-instruction-stops-systick-timer

However, I am not using these instructions in my multiprotocol application but are these instructions called by any of the SDK file related to BLE or Zigbee when I call nrf_sdh_enable_request()?