TMS320F28P650DK: EtherCAT 与F28 访问的问题

你好，请问CPU访问EtherCAT是按照字去访问嘛？为什么访问的时候offset要除以2呢？memcpy的时候除以了2不会减少实际传输的数据大小嘛？

void
ESC_writeBlockISR(ESCMEM_ADDR *pData, uint16_t address, uint16_t len)
{
    uint16_t wordValue;

    //
    // Create pointer to ESC Address
    //
    void * escDest = (void *)(ESC_BASE + (uint32_t)(address / 2U));

    //
    // Determine if length (in bytes) is even or odd
    //
    if((len & 0x1U) == 0x1U)
    {
        //
        // Odd Length
        //

        //
        // Copy even bytes of buffer data to ESC memory.
        // Convert length to words.
        //
        memcpy(escDest, pData, (size_t)((len - 1U) >> 1U));

        //
        // Read last 16-bit word
        //
        wordValue = ESC_readWordISR(address + (len - 1U));

        //
        // Modify word data and set new data
        //
        wordValue &= ESC_M_MSB;
        wordValue |= (pData[((len - 1U) / 2U)] & ESC_M_LSB);

        //
        // Write modified value to ESC destination
        //
        ESC_writeWordISR(wordValue, (address + (len - 1U)));
    }
    else
    {
        //
        // Even Length
        //

        //
        // Copy buffer data to ESC memory. Convert length to words.
        //
        memcpy(escDest, pData, (size_t)(len >> 1U));
    }
}