6.2. SDI Audio Extract Registers
The following tables list the registers for the SDI Audio Extract IP core.
Bytes Offset |
Name |
---|---|
00h |
Audio Control Register |
01h |
Audio Presence Register |
02h |
Audio Status Register |
03h |
SD EDP Presence Register |
04h |
Error Status Register |
05h |
Reserved |
06h |
FIFO Status Register |
07h |
Clock Status Register |
08h-09h |
Reserved |
10h-3Fh |
Channel Status RAM (0×00), (0×01), ... (0×2F) |
Bit |
Name |
Access |
Description |
---|---|---|---|
Audio Control Register |
|||
0 |
Enable |
RW |
Enables the audio extraction component and internal AES output. |
3:1 |
Extract pair |
RW |
Defines the audio pair that the component extracts. For example:
|
4 |
Extract pair MSB |
RW |
For 3G-SDI Level A standard, this field extends the extract pair field to allow for future implementations with 32 embedded audio channels. For 3G-SDI Level B standard, this field selects the active video half of the 3G multiplex. |
5 |
Mute |
RW |
Drive this register high to mute the audio output. |
7:6 |
Unused |
— |
Reserved for future use. |
Audio Presence Register |
|||
3:0 |
Data packet present |
RO |
Reports which audio data groups are detected in the SDI stream. The following bits correspond to the number of audio groups detected:
|
7:4 |
Control packet present |
RO |
Reports which audio control packets are detected in the SDI stream. |
Audio Status Register |
|||
3:0 |
Active channel |
RO |
Reflects the lower four bits of the active channel field of the audio control packet. |
4 |
Asynchronous |
RO |
Reflects the asx bit (synchronous mode bit) of the RATE (sampling rate) field of the audio control packet. |
6:5 |
Sample rate |
RO |
Reports the X1 and X0 bits of the sample rate code from the RATE field of the audio control packet. |
7 |
Status valid |
RO |
Set to 1b when the audio control packet is present in the video stream. |
SD EDP Presence Register |
|||
3:0 |
EDP Present |
RO |
Reports which audio extended data groups are detected in the SD-SDI stream. |
7:4 |
Unused |
— |
Reserved for future use. |
Error Status Register |
|||
3:0 |
Error counter |
RW |
Counts up to 15 errors since last reset. Write 1b to any bit of this field to reset the entire counter to zero. |
4 |
Ancillary CS fail |
RW |
Indicates that an error has been detected in the ancillary packet checksum. This bit stays set until cleared by writing 1b to this register. |
5 |
Ancillary parity fail |
RW |
Indicates that an error has been detected in at least one of the parity fields:
|
6 |
Channel status CRC fail |
RW |
Indicates that an error has been detected in the channel status CRC. This bit stays set until cleared by writing 1b to this register. |
7 |
Audio packet ECRC fail |
RW |
Indicates that an error has been detected in the ECRC that forms part of the HD audio data packet. This bit stays set until cleared. To clear, write 1b to this register. |
FIFO Status Register |
|||
6:0 |
FIFO fill level |
RO |
Reports the amount of data in either the audio output FIFO or the Avalon-ST audio FIFO when the optional Avalon-ST Audio interface is used. |
7 |
Overflow/underflow |
RW |
This register bit goes high if one of the following occurs (based on the output mode used):
|
Clock Status Register |
|||
4:0 |
Offset |
RO |
Defines the frequency of the generated audio. |
6:5 |
Unused |
— |
Reserved for future use. |
7 |
74.17-MHz video clock |
RO |
To create a 48-kHz signal synchronous to the video clock, you must detect whether a 1 or 1/1.001 video clock rate is used. If you detect a 1/1.001 video clock rate, this field returns high. |
Channel Status RAM |
|||
7:0 |
Channel status data |
WO |
Read accesses within the address range 10h to 3Fh to the channel status RAM. This field returns the 24 bytes of channel status for X channel starting at address 10h, and the 24 bytes of channel status for Y channel starting at address 28h. |