示例代码中的中断条件在哪里

如何解决示例代码中的中断条件在哪里

中断是当我们停止主代码运行子代码时。 在下面的示例中，我们的中断代码是一个名为USART1_TX_IRQHandler的函数。

在这两行中，NVIC_enable表示USART1_TX_IRQn是我们的中断函数。

NVIC_ClearPendingIRQ(USART1_TX_IRQn);
    NVIC_EnableIRQ(USART1_TX_IRQn);

但是我在代码中看不到代码，在调用USART1_TX_IRQHandler之前我们已经检查过了。 我如何在代码中看到我们可以知道将要调用USART1_TX_IRQHandler的条件？ 谢谢。

#include "em_device.h"
#include "em_chip.h"
#include "em_cmu.h"
#include "em_gpio.h"
#include "em_usart.h"
#include "em_ldma.h"

#define TX_BUFFER_SIZE   10
#define RX_BUFFER_SIZE   TX_BUFFER_SIZE

uint8_t TxBuffer[TX_BUFFER_SIZE] = {0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09};
uint32_t TxBufferIndex = 0;

uint8_t RxBuffer[RX_BUFFER_SIZE] = {0};
uint32_t RxBufferIndex = 0;

/**************************************************************************//**
 * @brief USART1 TX IRQ Handler
 *****************************************************************************/
void USART1_TX_IRQHandler(void)
{
  // Send and receive incoming data
  USART_Tx(USART1,TxBuffer[TxBufferIndex++]);

  // Stop sending once we've gone through the whole TxBuffer
  if (TxBufferIndex == TX_BUFFER_SIZE)
  {
    TxBufferIndex = 0;
  }
}

/**************************************************************************//**
 * @brief USART1 RX IRQ Handler
 *****************************************************************************/
void USART1_RX_IRQHandler(void)
{
  // Send and receive incoming data
  RxBuffer[RxBufferIndex++] = USART_Rx(USART1);

  // Stop once we've filled up our buffer
  if (RxBufferIndex == RX_BUFFER_SIZE)
  {
    // Place breakpoint here and observe RxBuffer
    // RxBuffer should contain 0xA0,0xA1,0xA2,0xA3,0xA4,0xA5,0xA6,0xA7,0xA8,0xA9
    RxBufferIndex = 0;
  }
}

/**************************************************************************//**
 * @brief Initialize USART1
 *****************************************************************************/
void initUSART1 (void)
{
    CMU_ClockEnable(cmuClock_GPIO,true);
    CMU_ClockEnable(cmuClock_USART1,true);

    // Configure GPIO mode
    GPIO_PinModeSet(gpioPortC,8,gpioModePushPull,0); // US1_CLK is push pull
    GPIO_PinModeSet(gpioPortC,9,1); // US1_CS is push pull
    GPIO_PinModeSet(gpioPortC,6,1); // US1_TX (MOSI) is push pull
    GPIO_PinModeSet(gpioPortC,7,gpioModeInput,1);    // US1_RX (MISO) is input

    // Start with default config,then modify as necessary
    USART_InitSync_TypeDef config = USART_INITSYNC_DEFAULT;
    config.master       = true;            // master mode
    config.baudrate     = 1000000;         // CLK freq is 1 MHz
    config.autoCsEnable = true;            // CS pin controlled by hardware,not firmware
    config.clockMode    = usartClockMode0; // clock idle low,sample on rising/first edge
    config.msbf         = true;            // send MSB first
    config.enable       = usartDisable;    // Make sure to keep USART disabled until it's all set up
    USART_InitSync(USART1,&config);

    // Set USART pin locations
    USART1->ROUTELOC0 = (USART_ROUTELOC0_CLKLOC_LOC11) | // US1_CLK       on location 11 = PC8 per datasheet section 6.4 = EXP Header pin 8
                        (USART_ROUTELOC0_CSLOC_LOC11)  | // US1_CS        on location 11 = PC9 per datasheet section 6.4 = EXP Header pin 10
                        (USART_ROUTELOC0_TXLOC_LOC11)  | // US1_TX (MOSI) on location 11 = PC6 per datasheet section 6.4 = EXP Header pin 4
                        (USART_ROUTELOC0_RXLOC_LOC11);   // US1_RX (MISO) on location 11 = PC7 per datasheet section 6.4 = EXP Header pin 6

    // Enable USART pins
    USART1->ROUTEPEN = USART_ROUTEPEN_CLKPEN | USART_ROUTEPEN_CSPEN | USART_ROUTEPEN_TXPEN | USART_ROUTEPEN_RXPEN;

    // Enabling TX interrupts to transfer whenever
    // there is room in the transmit buffer
    USART_IntClear(USART1,USART_IF_TXBL);
    USART_IntEnable(USART1,USART_IEN_TXBL);
    NVIC_ClearPendingIRQ(USART1_TX_IRQn);
    NVIC_EnableIRQ(USART1_TX_IRQn);

    // Enabling RX interrupts to trigger whenever
    // a new packet arrives from the slave
    USART_IntClear(USART1,USART_IF_RXDATAV);
    USART_IntEnable(USART1,USART_IEN_RXDATAV);
    NVIC_ClearPendingIRQ(USART1_RX_IRQn);
    NVIC_EnableIRQ(USART1_RX_IRQn);

    // Enable USART1
    USART_Enable(USART1,usartEnable);
}

/**************************************************************************//**
 * @brief Main function
 *****************************************************************************/
int main(void)
{
  // Initialize chip
  CHIP_Init();

  // Initialize USART1 as SPI master
  initUSART1();

  // After the USART is initialized transfers will automatically start based off of certain interrupt flag conditions
  // A new packet will be sent to the slave whenever the TX Buffer is empty after a previous successful transfer
  // and a packet will be sent from the slave back whenever it receives a packet from the master and will be handled
  // by the USART_RX_IRQHandler
  while(1);
}