GS2970 datasheet(86/145 Pages) SEMTECH

86 / 145 page

GS2970 3Gb/s, HD, SD SDI Receiver Complete with

SMPTE Audio and Video Processing

Data Sheet

47478 - 4

September 2012

86 of 145

When the OS_SEL[1:0] bits are set for 6-sample pointer offset, no boundary-checking is

performed.

In HD mode the audio FIFO is a maximum of 10 samples deep. According to SMPTE

299M, audio samples are multiplexed immediately in the next HANC region after the

audio sample occurs.

4.19.3.4 Audio Crosspoint Block

The Audio Crosspoint is used for audio output channel re-mapping. This feature allows

any of the selected audio channels in Group A or Group B to be output on any of the eight

output channels. The default setting is for one to one mapping, where AOUT_1/2 is

extracted from Group A CH1 and CH2, AOUT_3/4 is extracted from Group A CH3 and

CH4, and so on.

NOTE: If audio samples from embedded audio packets with the group set in IDA[1:0] are

to be paired with samples from the group set in IDB[1:0], all of the channels must have

been derived from the same Word Clock and must be synchronous.

The output channel is set in the OPn_SRC[2:0] host interface registers. Table 4-22 lists the

3-bit address for audio channel mapping.

Table 4-21: Audio Buffer Pointer Offset Settings

OS_SEL[1:0]

Buffer Pointer Offset

26 samples (default)

12 samples

6 samples

Table 4-22: Audio Channel Mapping Codes

Audio Output Channel

3-bit Host Interface

Source Address

1000

2001

3010

4011

5100

101

7110

8111

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