DisplayPort Audio - 3.1 English

DisplayPort 1.4 RX Subsystem Product Guide (PG300)

Document ID
PG300
Release Date
2024-05-30
Version
3.1 English
Table 1. DisplayPort Audio
Offset Access Type Description
12'h300 R/W

RX_AUDIO_CONTROL. This register enables audio stream packets in main link.

[5:4]: MST Audio Stream no. N/A for SST

[3]: Audio Enable for STREAM 4 in MST. N/A for SST

[2]: Audio Enable for STREAM 3 in MST. N/A for SST

[1]: Audio Enable for STREAM 2 in MST. N/A for SST

[0]: Audio Enable for SST. In MST, Audio Enable for STREAM 1

12'h304 RO

RX_AUDIO_INFO_DATA

[31:0] Word formatted as per CEA 861-C Info Frame. Total of eight words should be read.

First word

  • [31:24] = HB3
  • [23:16] = HB2
  • [15:8] = HB1
  • [7:0] = HB0

Second word - DB3,DB2,DB1,DB0

....

Eighth word - DB27,DB26,DB25,DB24

The data bytes DB1...DBN of CEA Info frame are mapped as DB0-DBN-1. Info frame data is copied into these registers (read only).

12'h324 RO

RX_AUDIO_MAUD. M value of audio stream as decoded from Audio time stamp packet by the sink (read only).

[31:24] - Reserved

[23:0] - MAUD

12'h328 RO

RX_AUDIO_NAUD. N value of audio stream as decoded from Audio time stamp packet by the sink (read only).

[31:24] - Reserved

[23:0] - NAUD

12'h32C RO

RX_AUDIO_STATUS.

[9] - Extension Packet Received. Resets automatically after all words (9) are read. Blocks new packet until host reads the data.

[8:3] - Reserved

[2:1] - RS Decoder Error Counter. Used for debugging purpose.

[0] - Info Packet Received. Resets automatically after all info words (eight) are read. Blocks new packet until host reads the data.

12'h330 to 12'h350 RO

RX_SDP_EXT_DATA

[31:0] - Word formatted as per extension packet described in protocol standard. Packet length is fixed to 32 bytes in Sink controller.

You should convey this information to Source using the vendor fields and ensure proper packet size transmission is done by the Source controller. Total of nine words should be read. Extension packet address space can be used to hold the audio copy management packet/ISRC packet/VSC packets.

First word

  • [31:24] = HB3
  • [23:16] = HB2
  • [15:8] = HB1
  • [7:0] = HB0

Second word - DB3,DB2,DB1,DB0

....

Ninth word - DB31,DB30,DB29,DB28

Extension packet data is copied into these registers (read only). This is a key-hole memory. So, nine reads from this address space is required.