RADIO_IRQn can only be enabled per NVIC_EnableIRQ if Multiprotocol Support?

[Darrew]

My application (nRF51 S130 v2.0.1 SDK12.3.0) uses the Radio Timeslot feature for multiprotocol support similarly to the example in https://github.com/NordicPlayground/nrf51-ble-micro-esb-uart.

On calling sd_nvic_SetPriority(RADIO_IRQn, RADIO_IRQ_PRIORITY); in TIMESLOT_BEGIN_IRQHandler the following error shows up:

NRF_ERROR_SOC_NVIC_INTERRUPT_NOT_AVAILABLE

Why is RADIO_IRQn not available?

[ovrebekk]

Hi José

When using the SoftDevice the radio interrupt is not available, whether or not you are in a timeslot. Radio interrupts will trigger the interrupt handler in the SoftDevice, and events will have to be forwarded from there. 

When in a timeslot radio interrupts are forwarded to the application through timeslot signals, and will trigger the signal handler with the signal_type set to NRF_RADIO_CALLBACK_SIGNAL_TYPE_RADIO. When this signal occurs you can handle the interrupt in a similar way, and check the various event registers to see which of the radio events triggered the interrupt. 

if you take a look at the implementation in the nrf51-ble-micro-esb-uart example you can see that the RADIO_IRQHandler() function is called explicitly from the signal handler (line 174 of esb_timeslot.c):

case NRF_RADIO_CALLBACK_SIGNAL_TYPE_RADIO:
   signal_callback_return_param.params.request.p_next = NULL;
   signal_callback_return_param.callback_action = NRF_RADIO_SIGNAL_CALLBACK_ACTION_NONE;
   ESB_TIMESLOT_DEBUG_PIN_SET(ESB_TIMESLOT_DBG_PIN_RADIO_IRQHANDLER);
   RADIO_IRQHandler();
   ESB_TIMESLOT_DEBUG_PIN_CLEAR(ESB_TIMESLOT_DBG_PIN_RADIO_IRQHANDLER);
   break;

Best regards
Torbjørn

 

[Darrew]

Hi,

RADIO_IRQn is enabled per NVIC_EnableIRQ() in the example nrf51-ble-micro-esb-uart when calling TIMESLOT_BEGIN_IRQHandler. Does this make sense according to your statement?

On the other hand, when using the Softdevice, how can change the pririty level of the RADIO_IRQn?

BR

[ovrebekk]

Hi José

You can't change the interrupt priority directly in a timeslot. All the signals will be forwarded at interrupt priority 0 (the highest). 

If you want to run the interrupt at a lower priority I would recommend deferring execution to a lower interrupt context, either by setting a software interrupt in the signal handler, or by using something like the app_scheduler module to schedule the code to be run from the main context. 

Best regards
Torbjørn

[Darrew]

Hi,

RADIO_IRQn is enabled per NVIC_EnableIRQ() in the example nrf51-ble-micro-esb-uart when calling TIMESLOT_BEGIN_IRQHandler. Does this make sense according to your statement?

Our experience says that RADIO_IRQn must be enabled per NVIC_EnableIRQ in order to get signal RADIO per callback. Can you please confirm this?

BR

[ovrebekk]

Hi

It will be called implicitly through nrf_esb_init(..), that is correct, but I don't think this is strictly necessary. 

I would have to do some testing to be sure though ;)

Best regards
Torbjørn