Interrupt Priority

anbui — Mon, 04 Apr 2016 21:22:29 GMT

Where can i find the default interrupt priority for the dspi, i2c, and gpio drivers for the freedom k22f board.

Re: Interrupt Priority

Hui_Ma — Tue, 05 Apr 2016 06:39:03 GMT

Kinetis K22 product using ARM Cortex-M4 core. The interrupt priority setting at NVIC_IPRx register.

Please refer below code to set interrupt priority:

/*ARM Cortex M4 implementation for interrupt priority shift*/

#define ARM_INTERRUPT_LEVEL_BITS 4

/***********************************************************************/

* Initialize the NVIC to set specified IRQ priority.

* NOTE: The function only initializes the NVIC to set a single IRQ priority.

* Interrupts will also need to be enabled in the ARM core. This can be

* done using the EnableInterrupts macro.

* Parameters:

* irq irq number to be enabled (the irq number NOT the vector number)

* prio irq priority. 0-15 levels. 0 max priority

void set_irq_priority (int irq, int prio)

{

/*irq priority pointer*/

uint8 *prio_reg;

/* Make sure that the IRQ is an allowable number. Right now up to 105 is

* used.

if (irq > 105)

printf("\nERR! Invalid IRQ value passed to priority irq function!\n");

if (prio > 15)

printf("\nERR! Invalid priority value passed to priority irq function!\n");

/* Determine which of the NVICIPx corresponds to the irq */

prio_reg = (uint8 *)(((uint32)&NVICIP0) + irq);

/* Assign priority to IRQ */

*prio_reg = ( (prio&0xF) << (8 - ARM_INTERRUPT_LEVEL_BITS) );

}

/***********************************************************************/

Wish it helps.

Have a great day,
Ma Hui
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Interrupt Priority

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