How is ESB_EVT_IRQHandler started?

[Yas]

Hi

How is the ESB_EVT_IRQHandler started? NVIC_SetPendingIRQ(ESB_EVT_IRQ) ​​is registered with on_radio_disabled(), but I don't know how to be started this handler in the nrf_esb.c code.
I know that using ppi_init() to connect events and tasks between RADIO and NRF_ESB_SYS_TIMER (actually TIMER2). However the vector for ESB_EVT_IRQHandler is SWI0_IRQHandler(SWI0_EGU0_IRQHandler), so I don't find out how to start the ESB_EVT_IRQHandler. please tell me how TIMER2 is involved in starting ESB_EVT_IRQHandler.

Thanks in advance

Yas

[Yas]

Hi Torbjørn

Thank you for your continuous advice.
I might be misunderstanding something fundamental regarding the mechanism in NVIC.

ovrebekk said:

I think I can count 6 places in nrf_esb.c (from nRF5 SDK v17.1.0) where NVIC_SetPendingIRQ(ESB_EVT_IRQ); is called from one of the on_radio_disabled_xx functions. 

Sure, I know that 6 lines of the NVIC_SetPendingIRQ(ESB_EVT_IRQ) are placed in there.
I am assuming this is just reserving the ESB_EVT_IRQ to wait for an interrupt because the name is "NVIC_SetPendingIRQ" and it is not "NVIC_ClearPendingIRQ" and not call the ESB_EVT_IRQHander directly, am I wrong?

Best regards,

Yas

[ovrebekk]

Hi Yas

Yas said:

Sure, I know that 6 lines of the NVIC_SetPendingIRQ(ESB_EVT_IRQ) are placed in there.
I am assuming this is just reserving the ESB_EVT_IRQ to wait for an interrupt because the name is "NVIC_SetPendingIRQ" and it is not "NVIC_ClearPendingIRQ" and not call the ESB_EVT_IRQHander directly, am I wrong?

Setting the pending flag from software has the exact same effect as when a hardware peripheral triggers an interrupt. It will cause the ESB_EVT_IRQ handler to be called as soon as any higher priority interrupts have finished. 

In other words these 6 lines will trigger the handler to be called, they are not just configuring the interrupt. 

This is a software interrupt, which means there is no other way to fire the interrupt than to set the pending flag. 

NVIC_ClearPendingIRQ is normally not used, since the interrupt handler will clear the pending flag automatically. 

Best regards
Torbjørn

[Yas]

Hi Torbjørn

Thank you for your response.

ovrebekk said:

Setting the pending flag from software has the exact same effect as when a hardware peripheral triggers an interrupt. It will cause the ESB_EVT_IRQ handler to be called as soon as any higher priority interrupts have finished. 

Thank to you, I'm cleared about that now.
I can proceed forward. Thank you so much!

Best regards

Yas

[ovrebekk]

Hi Yas

Good to hear that things are clear. I will consider the case resolved then

Best regards
Torbjørn