如何设置STM32内核异常优先级 优先级, 如何

yuyang911220

• /**
• * @brief  Set the priority for an interrupt
• *
• * @param  IRQn      The number of the interrupt for set priority
• * @param  priority  The priority to set
• *
• * Set the priority for the specified interrupt. The interrupt  
• * number can be positive to specify an external (device specific)  
• * interrupt, or negative to specify an internal (core) interrupt.
• *
• * Note: The priority cannot be set for every core interrupt.
• */
  
• static __INLINE void NVIC_SetPriority(IRQn_Type IRQn, uint32_t priority)  
• {  
•   if(IRQn < 0) {  
•     SCB->SHP[((uint32_t)(IRQn) & 0xF)-4] = ((priority << (8 - __NVIC_PRIO_BITS)) & 0xff); } /* set Priority for Cortex-M3 System Interrupts */
  
•   else {  
•     NVIC->IP[(uint32_t)(IRQn)] = ((priority << (8 - __NVIC_PRIO_BITS)) & 0xff);} /* set Priority for device specific Interrupts  */
  
• }  

对于使用cm3内核的stm32来说，中断既包括内核异常也包括外设中断。以上代码用来设置中断优先级，代码来自3.5外设库中的core_cm3.h文件。可以对内核中断进行配置，也可以对外设进行中断优先级配置。对内和和外设中断优先级设置的寄存器不同，内核对应的是SHPRx寄存器组，而外设对应的是NVIC_IPRx寄存器组。

SYSTICK使用core_cm3.h文件进行配置时，默认的优先级配置为15，最低优先级。
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• NVIC_SetPriority (SysTick_IRQn, (1<<__NVIC_PRIO_BITS) - 1); //NVIC_PRIO_BITS为常数4 (1<<4-1 = 15)优先级最低。
  

[cpp] view plaincopy

• /**
• * @brief  Initialize and start the SysTick counter and its interrupt.
• *
• * @param   ticks   number of ticks between two interrupts
• * @return  1 = failed, 0 = successful
• *
• * Initialise the system tick timer and its interrupt and start the
• * system tick timer / counter in free running mode to generate  
• * periodical interrupts.
• */
  
• static __INLINE uint32_t SysTick_Config(uint32_t ticks)  
• {   
•   if (ticks > SysTick_LOAD_RELOAD_Msk)  return (1);            /* Reload value impossible */
  
• 
  
•   SysTick->LOAD  = (ticks & SysTick_LOAD_RELOAD_Msk) - 1;      /* set reload register */
  
•   NVIC_SetPriority (SysTick_IRQn, (1<<__NVIC_PRIO_BITS) - 1);  /* set Priority for Cortex-M0 System Interrupts */
  
•   SysTick->VAL   = 0;                                          /* Load the SysTick Counter Value */
  
•   SysTick->CTRL  = SysTick_CTRL_CLKSOURCE_Msk |   
•                    SysTick_CTRL_TICKINT_Msk   |   
•                    SysTick_CTRL_ENABLE_Msk;                    /* Enable SysTick IRQ and SysTick Timer */
  
•   return (0);                                                  /* Function successful */
  
• }