EZI2C的读写疑问

#include <project.h>

#include <header.h>



/* EZI2C slave buffer for write and read */

uint8 ezI2cBuffer[BUFFER_SIZE] = {PACKET_SOP, STS_CMD_FAIL, PACKET_EOP, PACKET_SOP, STS_CMD_FAIL, PACKET_EOP};





/*******************************************************************************

* Function Name: main

********************************************************************************

* Summary:

*  The main function performs the following actions:

*   1. Turns off RGB LED.

*   2. Sets up EZI2C slave buffer.

*   3. Starts I2C slave (SCB mode) component.

*   4. Enables global interrupts.

*   5. Waits for command from the I2C master to control the RGB LED.

*

* Parameters:

*  None

*

* Return:

*  None

*

*******************************************************************************/

void main()

{

    uint8 status = STS_CMD_FAIL;



    RGB_LED_OFF;



    /* Setup buffer and start EZI2C slave (SCB mode) */

    EZI2C_EzI2CSetBuffer1(BUFFER_SIZE, READ_ONLY_OFFSET, ezI2cBuffer);

    EZI2C_Start();



    CyGlobalIntEnable;



    for(;;)

    {

        /* Write complete: parse packet */

        if (0u != (EZI2C_EzI2CGetActivity() & EZI2C_EZI2C_STATUS_WRITE1))

        {

            /* Check start and end of packet markers */

            if ((ezI2cBuffer[PACKET_SOP_POS] == PACKET_SOP) &&

                (ezI2cBuffer[PACKET_EOP_POS] == PACKET_EOP))

            {

                status = ExecuteCommand(ezI2cBuffer[PACKET_CMD_POS]);

            }



            /* Update buffer with status */

            ezI2cBuffer[PACKET_STS_POS] = status;

            status = STS_CMD_FAIL;

        }



        /* Buffer is always available to be read */

    }

}





/*******************************************************************************

* ExecuteCommand(): executes received command and returns status

*******************************************************************************/

uint8 ExecuteCommand(uint32 cmd)

{

    uint8 status;



    status = STS_CMD_DONE;



    /* Execute received command */

    switch (cmd)

    {

        case CMD_SET_RED:

            RGB_LED_ON_RED;

            break;



        case CMD_SET_GREEN:

            RGB_LED_ON_GREEN;

            break;



        case CMD_SET_BLUE:

            RGB_LED_ON_BLUE;

            break;



        case CMD_SET_OFF:

            RGB_LED_OFF;

            break;



        default:

            status = STS_CMD_FAIL;

        break;

    }



    return(status);

}





/* [] END OF FILE */