A single packet buffer is provided for the extension packet. If the extension packet is available in the buffer, the packet is transmitted as soon as there is availability in the secondary channel. The packet length is fixed to eight words (32 bytes).
Use these steps to write an extended packet in the DisplayPort source controller.
1.Write nine words (as required) into the TX_AUDIO_EXT_DATA buffer.
2.Wait for the EXT_PKT_TXD interrupt.
3.Write the new packet (follow step 1).