问题出在函数 NVIC_GetPriority
- __STATIC_INLINE uint32_t NVIC_GetPriority(IRQn_Type IRQn)
- {
- if(IRQn < 0) {
- return((uint32_t)((SCB->SHP[_SHP_IDX(IRQn)] >> _BIT_SHIFT(IRQn) ) >> (8 - __NVIC_PRIO_BITS))); } /* get priority for Cortex-M0 system interrupts */
- else {
- return((uint32_t)((NVIC->IP[ _IP_IDX(IRQn)] >> _BIT_SHIFT(IRQn) ) >> (8 - __NVIC_PRIO_BITS))); } /* get priority for device specific interrupts */
- }
这里移位时发生了错误，高位没有去除。
例如：如果 IRQn == 26 ，并且 NVIC->IP[ _IP_IDX(IRQn)] == 0x40404040,
函数返回优先级为 0x101.
实际上正确的返回值应为 1
代码修正如下
- __STATIC_INLINE uint32_t NVIC_GetPriority(IRQn_Type IRQn)
- {
- if(IRQn < 0) {
- return 0xFF & ((uint32_t)((SCB->SHP[_SHP_IDX(IRQn)] >> _BIT_SHIFT(IRQn) ) >> (8 - __NVIC_PRIO_BITS))); } /* get priority for Cortex-M0 system interrupts */
- else {
- return 0xFF & ((uint32_t)((NVIC->IP[ _IP_IDX(IRQn)] >> _BIT_SHIFT(IRQn) ) >> (8 - __NVIC_PRIO_BITS))); } /* get priority for device specific interrupts */
- }
| 
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