GS2972 Datasheet, PDF (54/125 Pages) Semtech Corporation – 3G/HD/SD-SDI Serializer with Complete SMPTE Audio & Video Support

4.7.12 Audio Crosspoint
The GS2972 is capable of mapping any input channel to any Primary or Secondary
group channel.
Each group channel specifies the audio source using a 3-bit selector defined below in
Table 4-9:
Table 4-9: GS2972 SD Audio Crosspoint Channel Selection
Audio Source
Input channel 1
Input channel 2
Input channel 3
Input channel 4
Input channel 5
Input channel 6
Input channel 7
Input channel 8
SD Selector
000
001
010
011
100
101
110
111
HD/3G Selector
000
001
010
011
100
101
110
111
Each Primary and Secondary group channel specifies the audio source using the
following host interface fields:
Table 4-10: Audio Source Host Interface Fields
Host Interface Field Description
GPA_CH1_SRC[2:0]
GPA_CH2_SRC[2:0]
GPA_CH3_SRC[2:0]
GPA_CH4_SRC[2:0]
GPB_CH1_SRC[2:0]
GPB_CH2_SRC[2:0]
GPB_CH3_SRC[2:0]
GPB_CH4_SRC[2:0]
Primary Group Channel 1 Source Selector
Primary Group Channel 2 Source Selector
Primary Group Channel 3 Source Selector
Primary Group Channel 4 Source Selector
Secondary Group Channel 1 Source Selector
Secondary Group Channel 2 Source Selector
Secondary Group Channel 3 Source Selector
Secondary Group Channel 4 Source Selector
Default
000
001
010
011
100
101
110
111
Audio channels can be paired only when both channels are derived from the same Word
Clock and are synchronous.
The same audio channel cannot be used in both Primary and Secondary groups at the
same time.
The GS2972 asserts the XPOINT_ERROR host interface bit if any audio channel is
programmed to be included in both the Primary and Secondary groups.
GS2972 3G/HD/SD-SDI Serializer with Complete
SMPTE Audio & Video Support
Final Data Sheet Rev. 9
GENDOC-047479 September 2013
www.semtech.com
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