Posted on January 08, 2013 at 10:39
Just something about priority, I read this in PM0214 :
''If multiple pending exceptions have the same priority, the pending exception with the lowest
exception number takes precedence. For example, if both IRQ[0] and IRQ[1] are pending
and have the same priority, then IRQ[0] is processed before IRQ[1].''
And in RM0090 I see table with column ''Position'' and column ''Priority'' and not ''Exception number'' and ''IRQ Number'' ...
For me ''Position'' = ''Exception number'' and ''IRQ Number'' =''Priority'', isn't it?
A read also this in PM0214 2.3.6 (Rev 1) :
''To increase priority control in systems with interrupts, the NVIC supports priority grouping.
This divides each interrupt priority register entry into two fields:
�? An upper field that defines the group priority
�? A lower field that defines a subprioritywithin the group.
Only the group priority determines preemption of interrupt exceptions. When the processor
is executing an interrupt exception handler, another interrupt with the same group priority as
the interrupt being handled does not preempt the handler,
If multiple pending interrupts have the same group priority, the subpriority field determines
the order in which they are processed. If multiple pending interrupts have the same group
priority and subpriority, the interrupt with the lowest IRQ number is processed first.
For information about splitting the interrupt priority fields into group priority and subpriority,
see Application interrupt and reset control register (AIRCR) on page ''
So I think that I have just to use command :
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
And
NVIC_InitStruct.NVIC_IRQChannel = ADC_IRQn;
NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStruct.NVIC_IRQChannelSubPriority = 2;
NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStruct);
NVIC_InitStruct.NVIC_IRQChannel = DMA2_Stream0_IRQn;
NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStruct.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStruct);
This keep my SysTick Handler at higher priority ...
