[原创] 【国民技术车规MCU N32A455开发板】05、通过硬件I2C熟悉板载EEPROM的操作和应用

xld0932 2024-3-14 17:34 楼主

1.概述

国民技术N32A455系列MCU搭载了多达4个独立的I2C总线接口，它提供多主机功能，控制所有I2C总线特定的时序、协议、仲裁和定时。支持多种通信速率模式(最高支持1MHz)，支持DMA操作，同时与SMBus 2.0兼容。 I2C模块有多种用途，包括CRC码的生成和校验、 SMBus(系统管理总线—System Management Bus)和PMBus(电源管理总线—PowerManagement Bus)。

2.N32A455开发板EEPROM原理图

开发板选用EEROM芯片（CAT24C08YI-GT3），分别连接到硬件I2C1的PB8和PB9这两个引脚上，EEPROM的A0~A2地址选择引脚都连接了GND，如下所示：

3.I2C示例程序

通过I2C模块与外部EEPRON的通信，对EEPROM进行读取操作，熟悉I2C的编程和应用方法：

int main(void)
{
    uint16_t i = 0;

    log_init();
    log_info("this is a I2C EEPROM demo\r\n");
    /* Initialize the I2C EEPROM driver ----------------------------------------*/
    I2C_EE_Init();

    /* Fill the buffer to send */
    for (i = 0; i < TEST_EEPROM_SIZE; i++)
    {
        tx_buf[i] = i;
    }
    log_info("\r\nWrite to I2C EEPROM...");
    /* First write in the memory followed by a read of the written data --------*/
    /* Write to I2C EEPROM from TEST_EEPROM_ADDR */
    I2C_EE_WriteBuffer(tx_buf, TEST_EEPROM_ADDR, TEST_EEPROM_SIZE);

    log_info("\r\nRead from I2C EEPROM :");
    /* Read from I2C EEPROM from sEE_READ_ADDRESS1 */
    I2C_EE_ReadBuffer(rx_buf, TEST_EEPROM_ADDR, TEST_EEPROM_SIZE);

    for (i = 0; i < TEST_EEPROM_SIZE; i++)
    {
        if ((i % 16) == 0)
        {
            printf("\r\n");
        }

        printf("0x%02X ", rx_buf[i]);
    }

    printf("\r\n");

    /* Check if the data written to the memory is read correctly */
    test_status = Buffercmp(tx_buf, rx_buf, TEST_EEPROM_SIZE);

    if (test_status == PASSED)
    {
        log_info("\r\nthe write and read data are the same,I2C EEPROM test pass\r\n");
    }
    else
    {
        log_info("\r\nthe write and read data are different,I2C EEPROM test fail\r\n");
    }

    while (1)
    {
    }
}

EEPROM写PAGE操作：

写PAGE操作实现了查访和DMA两种方式，操作流程都相同，都是先产生START信号、发送器件地址、发送写入地址、写入数据、最后发送STOP停止位；每一个步骤都对应一个事件检测，判断是否操作完成：

void I2C_EE_PageWrite(u8* pBuffer, u16 WriteAddr, u16 NumByteToWrite)
{
#if PROCESS_MODE == 0 /* polling */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (I2C_GetFlag(I2Cx, I2C_FLAG_BUSY))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Send START condition */
    I2C_GenerateStart(I2Cx, ENABLE);
    /** Test on EV5 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_MODE_FLAG))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Send EEPROM address for write */
    I2C_SendAddr7bit(I2Cx, EEPROM_ADDRESS, I2C_DIRECTION_SEND);
    /** Test on EV6 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_TXMODE_FLAG))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Send the EEPROM's internal address to write to */
    I2C_SendData(I2Cx, WriteAddr);
    /** Test on EV8 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_DATA_SENDED))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** While there is data to be written */
    while (NumByteToWrite--)
    {
        /** Send the current byte */
        I2C_SendData(I2Cx, *pBuffer);
        /** Point to the next byte to be written */
        pBuffer++;
        /** Test on EV8 and clear it */
        sEETimeout = sEE_LONG_TIMEOUT;
        while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_DATA_SENDED))
        {
            if ((sEETimeout--) == 0)
                sEE_TIMEOUT_UserCallback();
        }
    }
    /** Send STOP condition */
    I2C_GenerateStop(I2Cx, ENABLE);
    I2C_EE_WaitEepromStandbyState();
    I2C_EE_WriteOnePageCompleted();

#elif PROCESS_MODE == 1 /* interrupt */
    /** initialize static parameter */
    MasterDirection = Transmitter;
    i2c_comm_state  = COMM_PRE;
    /** initialize static parameter according to input parameter */
    SlaveADDR    = EEPROM_ADDRESS; /// this byte shoule be send by F/W (in loop or INTSTS way)
    DeviceOffset = WriteAddr;      /// this byte can be send by both F/W and DMA
    OffsetDone   = FALSE;
    memcpy(SendBuf, pBuffer, NumByteToWrite);
    BufCount           = 0;
    Int_NumByteToWrite = NumByteToWrite;
    I2C_ConfigAck(I2C1, ENABLE);
    I2C_ConfigInt(I2C1, I2C_INT_EVENT | I2C_INT_BUF | I2C_INT_ERR, ENABLE);

    /** Send START condition */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (I2C_GetFlag(I2Cx, I2C_FLAG_BYTEF))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    I2C_GenerateStart(I2C1, ENABLE);
    I2C_EE_WaitOperationIsCompleted();
    I2C_EE_WriteOnePageCompleted();

#elif PROCESS_MODE == 2 /* DMA */
    DMA_InitType DMA_InitStructure;
    /** DMA initialization */
    DMA_DeInit(DMA1_CH6);
    DMA_InitStructure.PeriphAddr     = (u32)&I2Cx->DAT;            /// (u32)I2C1_DR_Address;
    DMA_InitStructure.MemAddr        = (u32)pBuffer;              /// from function input parameter
    DMA_InitStructure.Direction      = DMA_DIR_PERIPH_DST;     /// fixed for send function
    DMA_InitStructure.BufSize        = NumByteToWrite;            /// from function input parameter
    DMA_InitStructure.PeriphInc      = DMA_PERIPH_INC_DISABLE; // fixed
    DMA_InitStructure.DMA_MemoryInc  = DMA_MEM_INC_ENABLE;      /// fixed
    DMA_InitStructure.PeriphDataSize = DMA_PERIPH_DATA_SIZE_BYTE;  /// fixed
    DMA_InitStructure.MemDataSize    = DMA_MemoryDataSize_Byte;  /// fixed
    DMA_InitStructure.CircularMode   = DMA_MODE_NORMAL;           /// fixed
    DMA_InitStructure.Priority       = DMA_PRIORITY_VERY_HIGH;     /// up to user
    DMA_InitStructure.Mem2Mem        = DMA_M2M_DISABLE;      /// fixed
    DMA_Init(DMA1_CH6, &DMA_InitStructure);

    sEETimeout     = sEE_LONG_TIMEOUT;
    while (I2C_GetFlag(I2Cx, I2C_FLAG_BUSY))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Send START condition */
    I2C_GenerateStart(I2Cx, ENABLE);
    /** Test on EV5 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_MODE_FLAG))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Send EEPROM address for write */
    I2C_SendAddr7bit(I2Cx, EEPROM_ADDRESS, I2C_DIRECTION_SEND);
    /** Test on EV6 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_TXMODE_FLAG))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Send the EEPROM's internal address to write to */
    I2C_SendData(I2Cx, WriteAddr);
    /** Test on EV8 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_DATA_SENDING))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    
    DMA_EnableChannel(DMA1_CH6, ENABLE);
    I2C_EnableDMA(I2C1, ENABLE);
    sEETimeout = sEE_LONG_TIMEOUT;
    while(I2C_GetFlag(I2Cx, I2C_FLAG_BYTEF))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Send STOP condition */
    I2C_GenerateStop(I2Cx, ENABLE);
    I2C_EnableDMA(I2Cx, DISABLE);
    DMA_EnableChannel(DMA1_CH6, DISABLE);
    I2C_EE_WaitEepromStandbyState();
    I2C_EE_WriteOnePageCompleted();
#endif
}

EEPROM读取数据：

EEPROM数据读取的函数，依然使用了查询和DMA两种实现方式，EEPROM的读取大小没有写入PAGE字节数的限制了；具体的操作流程：产生START信号、发送器件地址、发送读取地址、产生RESTART信号、发送读取命令、读取数据：

void I2C_EE_ReadBuffer(u8* pBuffer, u16 ReadAddr, u16 NumByteToRead)
{
#if PROCESS_MODE == 0 /* polling */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (I2C_GetFlag(I2Cx, I2C_FLAG_BUSY))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    I2C_ConfigNackLocation(I2Cx, I2C_NACK_POS_CURRENT);  // clear ACKPOS
    I2C_ConfigAck(I2Cx, ENABLE);
    /** Send START condition */
    I2C_GenerateStart(I2Cx, ENABLE);

    /** Test on EV5 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_MODE_FLAG))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Send EEPROM address for write */
    I2C_SendAddr7bit(I2Cx, EEPROM_ADDRESS, I2C_DIRECTION_SEND);
    /** Test on EV6 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_TXMODE_FLAG))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Clear EV6 by setting again the PE bit */
    I2C_Enable(I2Cx, ENABLE);
    /** Send the EEPROM's internal address to write to */
    I2C_SendData(I2Cx, ReadAddr);
    /** Test on EV8 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_DATA_SENDED))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Send STRAT condition a second time */
    I2C_GenerateStart(I2Cx, ENABLE);
    /** Test on EV5 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_MODE_FLAG))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Send EEPROM address for read */
    I2C_SendAddr7bit(I2Cx, EEPROM_ADDRESS, I2C_DIRECTION_RECV);
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_GetFlag(I2Cx, I2C_FLAG_ADDRF))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }

    /** While there is data to be read */
    if (NumByteToRead == 1)
    {
        /** Disable Acknowledgement */
        I2C_ConfigAck(I2Cx, DISABLE);
        (void)(I2Cx->STS1); /// clear ADDR
        (void)(I2Cx->STS2);
        I2C_GenerateStop(I2Cx, ENABLE);
    }
    else if (NumByteToRead == 2)
    {
        I2C_ConfigNackLocation(I2Cx, I2C_NACK_POS_NEXT);  // set ACKPOS
        (void)(I2Cx->STS1);
        (void)(I2Cx->STS2);
        I2C_ConfigAck(I2Cx, DISABLE);
    }
    else
    {
        I2C_ConfigAck(I2Cx, ENABLE);
        (void)(I2Cx->STS1);
        (void)(I2Cx->STS2);
    }
    while (NumByteToRead)
    {
        if (NumByteToRead <= 3)
        {
            /** One byte */
            if (NumByteToRead == 1)
            {
                /** Wait until RXNE flag is set */
                sEETimeout = sEE_LONG_TIMEOUT;
                while (!I2C_GetFlag(I2Cx, I2C_FLAG_RXDATNE))
                {
                    if ((sEETimeout--) == 0)
                        sEE_TIMEOUT_UserCallback();
                }
                /** Read data from DAT */
                /** Read a byte from the EEPROM */
                *pBuffer = I2C_RecvData(I2Cx);
                /** Point to the next location where the byte read will be saved */
                pBuffer++;
                /** Decrement the read bytes counter */
                NumByteToRead--;
            }
            /** Two bytes */
            else if (NumByteToRead == 2)
            {
                /** Wait until BTF flag is set */
                sEETimeout = sEE_LONG_TIMEOUT;
                while (!I2C_GetFlag(I2Cx, I2C_FLAG_BYTEF))
                {
                    if ((sEETimeout--) == 0)
                        sEE_TIMEOUT_UserCallback();
                }
                /** Send STOP Condition */
                I2C_GenerateStop(I2Cx, ENABLE);

                /** Read data from DAT */
                *pBuffer = I2C_RecvData(I2Cx);
                /** Point to the next location where the byte read will be saved */
                pBuffer++;
                /** Decrement the read bytes counter */
                NumByteToRead--;
                /** Read data from DAT */
                *pBuffer = I2C_RecvData(I2Cx);
                /** Point to the next location where the byte read will be saved */
                pBuffer++;
                /** Decrement the read bytes counter */
                NumByteToRead--;
            }
            /** 3 Last bytes */
            else
            {
                sEETimeout = sEE_LONG_TIMEOUT;
                while (!I2C_GetFlag(I2Cx, I2C_FLAG_BYTEF))
                {
                    if ((sEETimeout--) == 0)
                        sEE_TIMEOUT_UserCallback();
                }
                /** Disable Acknowledgement */
                I2C_ConfigAck(I2Cx, DISABLE);
                /** Read data from DAT */
                *pBuffer = I2C_RecvData(I2Cx);
                /** Point to the next location where the byte read will be saved */
                pBuffer++;
                /** Decrement the read bytes counter */
                NumByteToRead--;

                /** Wait until BTF flag is set */
                sEETimeout = sEE_LONG_TIMEOUT;
                while (!I2C_GetFlag(I2Cx, I2C_FLAG_BYTEF))
                {
                    if ((sEETimeout--) == 0)
                        sEE_TIMEOUT_UserCallback();
                }
                /** Send STOP Condition */
                I2C_GenerateStop(I2Cx, ENABLE);

                /** Read data from DAT */
                *pBuffer = I2C_RecvData(I2Cx);
                /** Point to the next location where the byte read will be saved */
                pBuffer++;
                /** Decrement the read bytes counter */
                NumByteToRead--;

                /** Read data from DAT */
                *pBuffer = I2C_RecvData(I2Cx);
                /** Point to the next location where the byte read will be saved */
                pBuffer++;
                /** Decrement the read bytes counter */
                NumByteToRead--;
            }
        }
        else
        {
            /** Test on EV7 and clear it */
            sEETimeout = sEE_LONG_TIMEOUT;
            while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_DATA_RECVD_FLAG))
            {
                if ((sEETimeout--) == 0)
                    sEE_TIMEOUT_UserCallback();
            }
            /** Read a byte from the EEPROM */
            *pBuffer = I2C_RecvData(I2Cx);
            /** Point to the next location where the byte read will be saved */
            pBuffer++;
            /** Decrement the read bytes counter */
            NumByteToRead--;
            if (I2C_GetFlag(I2Cx, I2C_FLAG_BYTEF))
            {
                /** Read a byte from the EEPROM */
                *pBuffer = I2C_RecvData(I2Cx);
                /** Point to the next location where the byte read will be saved */
                pBuffer++;
                /** Decrement the read bytes counter */
                NumByteToRead--;
            }
        }
    }

#elif PROCESS_MODE == 1 /* interrupt */
    I2C_pBuffer     = pBuffer;
    MasterDirection = Receiver;

    /** initialize static parameter according to input parameter*/
    SlaveADDR      = EEPROM_ADDRESS;
    DeviceOffset   = ReadAddr;
    OffsetDone     = FALSE;
    i2c_comm_state = COMM_PRE;
    I2C_ConfigNackLocation(I2Cx, I2C_NACK_POS_CURRENT);  // clear ACKPOS
    I2C_ConfigAck(I2C1, ENABLE);
    I2C_ConfigInt(I2C1, I2C_INT_EVENT | I2C_INT_BUF | I2C_INT_ERR, ENABLE);
    Int_NumByteToRead = NumByteToRead;

    sEETimeout = sEE_LONG_TIMEOUT;
    while (I2C_GetFlag(I2Cx, I2C_FLAG_BYTEF))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    I2C_GenerateStart(I2C1, ENABLE);
    I2C_EE_WaitOperationIsCompleted();

#elif PROCESS_MODE == 2 /* DMA */
    /** DMA initialization */
    if(NumByteToRead > 1)
    {
        DMA_InitType DMA_InitStructure;
        /** DMA initialization */
        DMA_DeInit(DMA1_CH7);
        DMA_InitStructure.PeriphAddr     = (u32)&I2Cx->DAT;            /// (u32)I2C1_DR_Address;
        DMA_InitStructure.MemAddr        = (u32)pBuffer;               /// from function input parameter
        DMA_InitStructure.Direction      = DMA_DIR_PERIPH_SRC;         /// fixed for read function
        DMA_InitStructure.BufSize        = NumByteToRead;              /// from function input parameter
        DMA_InitStructure.PeriphInc      = DMA_PERIPH_INC_DISABLE;     /// fixed
        DMA_InitStructure.DMA_MemoryInc  = DMA_MEM_INC_ENABLE;         /// fixed
        DMA_InitStructure.PeriphDataSize = DMA_PERIPH_DATA_SIZE_BYTE;  /// fixed
        DMA_InitStructure.MemDataSize    = DMA_MemoryDataSize_Byte;    /// fixed
        DMA_InitStructure.CircularMode   = DMA_MODE_NORMAL;            /// fixed
        DMA_InitStructure.Priority       = DMA_PRIORITY_VERY_HIGH;     /// up to user
        DMA_InitStructure.Mem2Mem        = DMA_M2M_DISABLE;            /// fixed
        DMA_Init(DMA1_CH7, &DMA_InitStructure);
    }
    while (I2C_GetFlag(I2Cx, I2C_FLAG_BUSY))
    {
        if ((sEETimeout--) == 0)
        {
            sEE_TIMEOUT_UserCallback();
        }
    }
    /** Send START condition */
    I2C_GenerateStart(I2Cx, ENABLE);
    /** Test on EV5 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_MODE_FLAG))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Send EEPROM address for write */
    I2C_SendAddr7bit(I2Cx, EEPROM_ADDRESS, I2C_DIRECTION_SEND);
    /** Test on EV6 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_TXMODE_FLAG))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Clear EV6 by setting again the PE bit */
    I2C_Enable(I2Cx, ENABLE);
    /** Send the EEPROM's internal address to write to */
    I2C_SendData(I2Cx, ReadAddr);
    /** Test on EV8 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_DATA_SENDED))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Send STRAT condition a second time */
    I2C_GenerateStart(I2Cx, ENABLE);
    /** Test on EV5 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_CheckEvent(I2Cx, I2C_EVT_MASTER_MODE_FLAG))
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** Send EEPROM address for read */
    I2C_SendAddr7bit(I2Cx, EEPROM_ADDRESS, I2C_DIRECTION_RECV);
    /* Test on EV6 and clear it */
    sEETimeout = sEE_LONG_TIMEOUT;
    while (!I2C_GetFlag(I2Cx, I2C_FLAG_ADDRF))    //EV6
    {
        if ((sEETimeout--) == 0)
            sEE_TIMEOUT_UserCallback();
    }
    /** While there is data to be read */
    if (NumByteToRead == 1)
    {
        /** Disable Acknowledgement */
        I2C_ConfigAck(I2Cx, DISABLE);
        (void)(I2Cx->STS1); /// clear ADDR
        (void)(I2Cx->STS2);
        I2C_GenerateStop(I2Cx, ENABLE);
        /** Wait until RXNE flag is set */
        sEETimeout = sEE_LONG_TIMEOUT;
        while (!I2C_GetFlag(I2Cx, I2C_FLAG_RXDATNE))
        {
            if ((sEETimeout--) == 0)
                sEE_TIMEOUT_UserCallback();
        }
        /** Read data from DAT */
        /** Read a byte from the EEPROM */
        *pBuffer = I2C_RecvData(I2Cx);
    }
    else
    {
      I2C_ConfigAck(I2Cx, ENABLE);
      (void)(I2Cx->STS1);
      (void)(I2Cx->STS2);
      I2C_EnableDmaLastSend(I2Cx, ENABLE);
      DMA_EnableChannel(DMA1_CH7, ENABLE);
      I2C_EnableDMA(I2Cx, ENABLE);
      sEETimeout = sEE_LONG_TIMEOUT;
      while(!(DMA_GetFlagStatus(DMA1_FLAG_TC7,DMA1)))
      {
          if ((sEETimeout--) == 0)
              sEE_TIMEOUT_UserCallback();
      }
      I2C_EnableDMA(I2Cx, DISABLE);
      DMA_EnableChannel(DMA1_CH7, DISABLE);
      I2C_EnableDmaLastSend(I2Cx, DISABLE);
      I2C_GenerateStop(I2Cx, ENABLE);
    }
    I2C_EE_WaitOperationIsCompleted();
#endif
}

4.运行结果