LPC1114的中斷,由中斷控制模組NVIC控制。一共32箇中斷,每個中斷的優先順序可程式設計為 0~3 四種級別。級別越高對應的優先順序越低。因此,級別0 是最高的中斷優先順序。

設定中斷優先順序的函式,CMISIS已經寫好,並嵌入到了編譯器中,例如,我們用KEIL開發的話,設定中斷優先順序的函式位於core_cm0.h檔案當中,函式如下所示:

/** \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)
{
  ) {
    SCB->SHP[_SHP_IDX(IRQn)] = (SCB->SHP[_SHP_IDX(IRQn)] & ~(0xFF << _BIT_SHIFT(IRQn))) |
    (((priority << ( - __NVIC_PRIO_BITS)) & 0xFF) << _BIT_SHIFT(IRQn)); }
  else {
    NVIC->IP[_IP_IDX(IRQn)] = (NVIC->IP[_IP_IDX(IRQn)] & ~(0xFF << _BIT_SHIFT(IRQn))) |
    (((priority << ( - __NVIC_PRIO_BITS)) & 0xFF) << _BIT_SHIFT(IRQn)); }
}

  從上面函式可以看出,該函式有兩個引數,IRQn是指你要設定的中斷向量,priority是中斷優先順序,優先順序可以是0 1 2 3四個數,0的優先順序最大,3的優先順序最小。假設你要設定GPIO1中斷的優先順序最高,那麼就是:

NVIC_SetPriority(EINT1_IRQn, 0);

  這時,有人會問,”EINT1_IRQn”從哪裡來?答:這個可以在LPC11xx.h檔案當中找到,如下所示:

/*
* ==========================================================================
* ---------- Interrupt Number Definition -----------------------------------
* ==========================================================================
*/
typedef enum IRQn
{
/****** Cortex-M0 Processor Exceptions Numbers ***************************************************/
Reset_IRQn = -, /*!< 1 Reset Vector, invoked on Power up and warm reset */
NonMaskableInt_IRQn = -, /*!< 2 Non maskable Interrupt, cannot be stopped or preempted */
HardFault_IRQn = -, /*!< 3 Hard Fault, all classes of Fault */
SVCall_IRQn = -, /*!< 11 System Service Call via SVC instruction */
PendSV_IRQn = -, /*!< 14 Pendable request for system service */
SysTick_IRQn = -, /*!< 15 System Tick Timer */

/****** LPC11Cxx or LPC11xx Specific Interrupt Numbers *******************************************************/
WAKEUP0_IRQn = , /*!< All I/O pins can be used as wakeup source. */
WAKEUP1_IRQn = , /*!< There are 13 pins in total for LPC11xx */
WAKEUP2_IRQn = ,
WAKEUP3_IRQn = ,
WAKEUP4_IRQn = ,
WAKEUP5_IRQn = ,
WAKEUP6_IRQn = ,
WAKEUP7_IRQn = ,
WAKEUP8_IRQn = ,
WAKEUP9_IRQn = ,
WAKEUP10_IRQn = ,
WAKEUP11_IRQn = ,
WAKEUP12_IRQn = ,
CAN_IRQn = , /*!< CAN Interrupt */
SSP1_IRQn = , /*!< SSP1 Interrupt */
I2C_IRQn = , /*!< I2C Interrupt */
TIMER_16_0_IRQn = , /*!< 16-bit Timer0 Interrupt */
TIMER_16_1_IRQn = , /*!< 16-bit Timer1 Interrupt */
TIMER_32_0_IRQn = , /*!< 32-bit Timer0 Interrupt */
TIMER_32_1_IRQn = , /*!< 32-bit Timer1 Interrupt */
SSP0_IRQn = , /*!< SSP0 Interrupt */
UART_IRQn = , /*!< UART Interrupt */
Reserved0_IRQn = , /*!< Reserved Interrupt */
Reserved1_IRQn = ,
ADC_IRQn = , /*!< A/D Converter Interrupt */
WDT_IRQn = , /*!< Watchdog timer Interrupt */
BOD_IRQn = , /*!< Brown Out Detect(BOD) Interrupt */
FMC_IRQn = , /*!< Flash Memory Controller Interrupt */
EINT3_IRQn = , /*!< External Interrupt 3 Interrupt */
EINT2_IRQn = , /*!< External Interrupt 2 Interrupt */
EINT1_IRQn = , /*!< External Interrupt 1 Interrupt */
EINT0_IRQn = , /*!< External Interrupt 0 Interrupt */
} IRQn_Type;