I2C Slave 中断回调函数 Case 使用说明

[quanfeng]

1. 问题背景

1. 软件：MD1 SDK 1_4_0 I2c_Slave_Demo
   I2c_Slave_Demo.zip
2. 硬件：MD14 EVB or 客户板子
3. 问题表述：

• I2C 从机模式时，客户想在回调函数里做处理，但不清楚回调函数里 Case 的使用情况。

2. Case 说明

1. I2C0_SlaveRxCpltCallback 函数

/*
    伪 C 语言代码，直接编译会报错
*/
void I2C0_SlaveRxCpltCallback(i2c_slave_event_t event, void *userData)
{
    /* Get the instance number from userData */
    uint32_t instance = 0;
    (void)userData;
    /* Depending on the event received, set the buffers or abort the transfer */
    switch (event)
    {
        case I2C_SLAVE_EVENT_RX_REQ:
            /*
             * If the bus master requests data, then set the destination RX buffer
             * and accepted transfer size
             */
              I2C_DRV_SlaveSetRxBuffer(instance, slaveRxBuffer, BUFF_SIZE);
            break;
        case I2C_SLAVE_EVENT_TX_REQ:
            /*
             * If the bus master sends data, then set the source TX buffer
             * and accepted transfer size
             */
              I2C_DRV_SlaveSetTxBuffer(instance, slaveTxBuffer, BUFF_SIZE);
            break;
        case I2C_SLAVE_EVENT_TX_EMPTY:
            /*
             * If the TX buffer is empty. Because the example does not handle 
             * this case there is no action taken.
             */
        case I2C_SLAVE_EVENT_RX_FULL:
            /*
             * If the RX buffer is full, check the slave receive buffer is correct
             */
            break;
        case I2C_SLAVE_EVENT_STOP:
            /*
             * This case is used when a stop condition is on the bus. Because
             * the example does not handle this case there is no action taken.
             */
            break;
    }  
}

3. 获取接收 Data 的个数

1. 使用 I2C_DRV_SlaveGetTransferStatus 函数可以获取 Data 接收的个数，I2C_DRV_SlaveSetTxBuffer 函数的第三个参数是当前 rxSize 的剩余长度，接收长度（已知） - bytesRemaining 得到当前接收了多少字节