Posted on May 17, 2011 at 14:07You need to configure the NVIC to have multiple levels of preemption and park the Timer 5 in a lower preemption level. Within a preemption group, higher subpriority levels have lower importance and will be serviced last as the M3 tail-chains from one pending interrupt, at the preemption level, to the next.
Replace EXTI9_5_IRQChannel with your timer 5 channel.
/* Configure one bit for preemption priority */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
/* Enable the EXTI9_5 Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQChannel;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
/* Set SysTick interrupt vector Preemption Priority to 1 */
NVIC_SystemHandlerPriorityConfig(SystemHandler_SysTick, 1, 0);
