freertos Uart example NVIC_setPriority question

[Seongyon_Jeong]

IMX RT1020-EVK board.  SDK info (SDK_2.x_EVK-MIMXRT1020,   SDK version 2.13.0)

After  import SDK example - Generated project evkmimxrt1020_freertos_lpuart

In this project,  Why NVIC_setPriority  func is needed ??   

If I do not call this func ,  Does LPUART1_IRQn  has priority 0 ?? , 

Why this make  program  running- Down ? (exactly, Once interruprt TX_IDLE Occur, and  Stopped(blocked?) ) 

and If set priority 2 or 3,4,5...   , it woks well.

but ,  IRQ priority is not set  in Other SDK Example  projects, for example,  xxxx_lpuart_interrupt ,  xxxx_lpuart_interrupt _rb_transfer, ..

so, Why  , Only evkmimxrt1020_freertos_lpuart - this Example,  do I need to set priority ?

[Miguel04 · Accepted solution]

Hi @Seongyon_Jeong 

If you are using FreeRTOS, it is needed to set the priority manually.

"Therefore, any interrupt service routine that uses an RTOS API function must have its priority manually set to a value that is numerically equal to or greater than the configMAX_SYSCALL_INTERRUPT_PRIORITY setting."

This information is from: freertos NVIC priority and FreeRTOS priority?.

Best Regards, Miguel.