On the output interface, the data is at audio frequency, each sample separated by 1/ƒs where ƒs = sampling frequency. Back pressure from PL to PS is not supported.
Table: PS-PL Signals for the Live Audio Interface shows the PS-PL interface signals for live audio interface. The audio_in group of signals is called the S_AXIS_AUDIO interface. The audio_out group of signals is called the M_AXIS_MIXED_AUDIO interface.
Table 33-6: PS-PL Signals for the Live Audio Interface
|
Signal Name
|
Type
|
Initial Value
|
Description
|
|
dp_s_axis_live_audio_tdata[31:0]
|
Input
|
–
|
Streaming data input.
[3:0] Preamble code (PR).
4'b0001 ® Subframe 1, start of audio block.
4'b0010 ® Subframe 1.
4'b0011 ® Subframe 2.
|
|
[27:4] Audio sample word.
|
|
[28] Validity bit (V).
|
|
[29] User bit (U).
|
|
[30] Channel status (C).
|
|
[31] Parity (P).
|
|
dp_s_axis_live_audio_tid
|
Input
|
–
|
Audio channel ID.
|
|
dp_s_axis_live_audio_tvalid
|
Input
|
–
|
Valid indicator for audio data from master.
|
|
dp_s_axis_live_audio_tready
|
Output
|
0
|
Ready indicator from DisplayPort controller.
|
|
dp_s_axis_audio_aclk
|
Input
|
–
|
Clock for AXI slave audio data input.
|
|
dp_m_axis_mixed_audio_tdata[31:0]
|
Output
|
0
|
Streaming data input.
[3:0] Preamble code (PR).
4'b0001 ® Subframe 1, start of audio block.
4'b0010 ® Subframe 1.
4'b0011 ® Subframe 2.
|
|
[27:4] Audio sample word.
|
|
[28] Validity bit (V).
|
|
[29] User bit (U).
|
|
[30] Channel status (C).
|
|
[31] Parity (P).
|
|
dp_m_axis_mixed_audio_tid
|
Output
|
0
|
Audio channel ID.
|
|
dp_m_axis_mixed_audio_tvalid
|
Output
|
0
|
Valid indicator for audio data from master.
|
|
dp_m_axis_mixed_audio_tready
|
Input
|
–
|
Ready indicator from PL
|
|
Notes:
1.The live audio interface needs to be synchronized with the dp_s_axis_audio_aclk signal.
|