Interrupt priority

Question

Hi, 
 While the softdevice is active (nRF51822) available interrupt priorities are: 
 typedef enum {
NRF_APP_PRIORITY_HIGH = 1,
NRF_APP_PRIORITY_LOW = 3
} nrf_app_irq_priority_t; 
 
 Can I use interrupt priority = 2? 
 SVC priority is 2, is it true? So I could't use Softdevice api-functions in interrupt handlers with NRF_APP_PRIORITY_HIGH priority? 
 What does define "#define NRF_APP_PRIORITY_THREAD 4" in app_util.h mean? 
 
 Artem Z.
Best Regards

Audun · Accepted Answer

Hi Artem, 
 to answer your questions 
 
 1. Can I use interrupt priority = 2? 
No, not while the SoftDevice is active. If you try to set this priority level using sd_nvic_SetPriority() you will get an error. 
 2. SVC priority is 2, is it true? So I could't use Softdevice api-functions in interrupt handlers with NRF_APP_PRIORITY_HIGH priority? 
Correct. You would need to pass execution to a lower priority level, for example by using a software interrupt (SWIRQ) with NRF_APP_PRIORITY_LOW. 
 3. What does define "#define NRF_APP_PRIORITY_THREAD 4" in app_util.h mean? 
It's used in "current_int_priority_get()" to indicate if the CPU is running in thread mode (main context), as opposed to running in interrupt mode with interrupt priority 0-3.

Interrupt priority

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