Systick priority

[philippe_chapus]

Posted on January 19, 2011 at 17:51

Systick priority

[philippe_chapus]

Posted on May 17, 2011 at 14:21

Hi,

Thank you clive1 for your rapid answer !!!

I have spend 1 day to find this bug, without success.

I hav'nt seen that Systick_Config() set the lowest priority, and it is called after my priority setting.

Philippe

[Tesla DeLorean]

Posted on May 17, 2011 at 14:21

Why are you setting the SubPriority?

  /* Configure the NVIC Preemption Priority Bits */

  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);

 NVIC_SetPriority(SysTick_IRQn, NVIC_EncodePriority(NVIC_GetPriorityGrouping(), 0, 0));

  /* Enable the USART3 Interrupt */

  NVIC_InitStructure.NVIC_IRQChannel                    = USART3_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority  = 1;

  NVIC_InitStructure.NVIC_IRQChannelSubPriority         = 0;

  NVIC_InitStructure.NVIC_IRQChannelCmd                 = ENABLE;

  NVIC_Init(&NVIC_InitStructure);   /* Enable the USART2 Interrupt  */

  NVIC_InitStructure.NVIC_IRQChannel                    = USART2_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority  = 2;

  NVIC_InitStructure.NVIC_IRQChannelSubPriority         = 0;

  NVIC_InitStructure.NVIC_IRQChannelCmd                 = ENABLE;

  NVIC_Init(&NVIC_InitStructure);

You should also consider setting the priority AFTER using Systick_Config(), because it sets the LOWEST priority.