<td>The output mux selection bits that selects the output  bit (start bit, serial data bit, parity bit, or stop bit). The value of those selection bits is decided according to the current state of the transmission.</td>
    </tr>
    <tr>
        <td>seial_data_index</td>
        <td>output</td>
        <td align="center">log<sub>2</sub>(DATA_WIDTH) (default value is 3)</td>
        <td>A number between 0 and 7 that indicates the index of the bit to be transmitted serially.</td>
    </tr>
    <tr>
        <