/** \brief Set Interrupt Priority
The function sets the priority of an interrupt.
\note The priority cannot be set for every core interrupt.
\param [in] IRQn Interrupt number.
\param [in] priority Priority to set.
*/
__STATIC_INLINE void NVIC_SetPriority(IRQn_Type IRQn, uint32_t priority)
{
if(IRQn < 0) {
SCB->SHP[_SHP_IDX(IRQn)] = (SCB->SHP[_SHP_IDX(IRQn)] & ~(0xFF << _BIT_SHIFT(IRQn))) |
(((priority << (8 - __NVIC_PRIO_BITS)) & 0xFF) << _BIT_SHIFT(IRQn)); }
else {
NVIC->IP[_IP_IDX(IRQn)] = (NVIC->IP[_IP_IDX(IRQn)] & ~(0xFF << _BIT_SHIFT(IRQn))) |
(((priority << (8 - __NVIC_PRIO_BITS)) & 0xFF) << _BIT_SHIFT(IRQn)); }
}
從上面函數可以看出，該函數有兩個參數，IRQn是指要設置的中斷向量，priority是中斷優先級，優先級可以是0 1 2 3四個數，0的優先級最大，3的優先級最小。假設妳要設置GPIO1中斷的優先級最高，那麽就是：
NVIC_SetPriority(EINT1_IRQn, 0);
這時，有人會問，”EINT1_IRQn”
答：這個可以在LPC11xx.h文件當中找到，如下所示：
/*
* ==========================================================================
* ---------- Interrupt Number Definition -----------------------------------
* ==========================================================================
*/
typedef enum IRQn
{
/****** Cortex-M0 Processor Exceptions Numbers ***************************************************/
Reset_IRQn = -15, /*!< 1 Reset Vector, invoked on Power up and warm reset */
NonMaskableInt_IRQn = -14, /*!< 2 Non maskable Interrupt, cannot be stopped or preempted */
HardFault_IRQn = -13, /*!< 3 Hard Fault, all classes of Fault */
SVCall_IRQn = -5, /*!< 11 System Service Call via SVC instruction */
PendSV_IRQn = -2, /*!< 14 Pendable request for system service */
SysTick_IRQn = -1, /*!< 15 System Tick Timer */
/****** LPC11Cxx or LPC11xx Specific Interrupt Numbers *******************************************************/
WAKEUP0_IRQn = 0, /*!< All I/O pins can be used as wakeup source. */
WAKEUP1_IRQn = 1, /*!< There are 13 pins in total for LPC11xx */
WAKEUP2_IRQn = 2,
WAKEUP3_IRQn = 3,
WAKEUP4_IRQn = 4,
WAKEUP5_IRQn = 5,
WAKEUP6_IRQn = 6,
WAKEUP7_IRQn = 7,
WAKEUP8_IRQn = 8,
WAKEUP9_IRQn = 9,
WAKEUP10_IRQn = 10,
WAKEUP11_IRQn = 11,
WAKEUP12_IRQn = 12,
CAN_IRQn = 13, /*!< CAN Interrupt */
SSP1_IRQn = 14, /*!< SSP1 Interrupt */
I2C_IRQn = 15, /*!< I2C Interrupt */
TIMER_16_0_IRQn = 16, /*!< 16-bit Timer0 Interrupt */
TIMER_16_1_IRQn = 17, /*!< 16-bit Timer1 Interrupt */
TIMER_32_0_IRQn = 18, /*!< 32-bit Timer0 Interrupt */
TIMER_32_1_IRQn = 19, /*!< 32-bit Timer1 Interrupt */
SSP0_IRQn = 20, /*!< SSP0 Interrupt */
UART_IRQn = 21, /*!< UART Interrupt */
Reserved0_IRQn = 22, /*!< Reserved Interrupt */
Reserved1_IRQn = 23,
ADC_IRQn = 24, /*!< A/D Converter Interrupt */
WDT_IRQn = 25, /*!< Watchdog timer Interrupt */
BOD_IRQn = 26, /*!< Brown Out Detect(BOD) Interrupt */
FMC_IRQn = 27, /*!< Flash Memory Controller Interrupt */
EINT3_IRQn = 28, /*!< External Interrupt 3 Interrupt */
EINT2_IRQn = 29, /*!< External Interrupt 2 Interrupt */
EINT1_IRQn = 30, /*!< External Interrupt 1 Interrupt */
EINT0_IRQn = 31, /*!< External Interrupt 0 Interrupt */
} IRQn_Type;