GS2972 Datasheet, PDF (61/125 Pages) Semtech Corporation – 3G/HD/SD-SDI Serializer with Complete SMPTE Audio & Video Support

When the frame rate is 29.97Hz, an even number of samples (8008) are distributed over
five frames in the following sequence:
1602 1601 1602 1601 1602
When the frame rate is 59.94Hz, an even number of samples (4004) are distributed over
five frames in the following sequence:
801 800 801 801 801
The GS2972 sets the AFN field to a number between one and five, depending on where
the current frame lies within the sequence.
The GS2972 adds the offset specified in the AFN_OFS host interface field to the
generated AFN. The result of the addition wraps around such that the AFN will always
be in the range of one to five.
4.7.19 ECC Error Detection and Correction
The GS2972 generates the error detection and correction fields in the audio data
packets.
The error detection and correction complies with SMPTE ST 299.
4.7.20 Audio Control Packet Insertion - SD
The GS2972 embeds audio control packets associated with the Primary Group audio and
the Secondary Group audio.
The Primary Group audio to be embedded is specified using the IDA[1:0] host interface
field (Address 400h).
The Secondary Group audio to be embedded is specified using the IDB[1:0] host
interface field.
The Primary Group audio control packets is embedded as commanded by the CTRA_ON
host interface bit. (Default is ON)
The Secondary Group audio control packets is embedded as commanded by the
CTRB_ON host interface bit. (Default is ON)
The Primary Group audio control packets is replaced as commanded by the CTR_AGR
host interface bit. (Default is OFF)
The Secondary Group audio control packets is replaced as commanded by the CTR_AGR
and ONE_AGR host interface bits. (Default is OFF)
The contents of the Primary Group audio control packet is specified using the following
host interface fields:
AFNA_AUTO Primary Group audio frame number generation.
EBIT1A Primary Group delay valid flag for channel 1.
DEL1A[25:0] Primary Group delay for channel 1.
EBIT2A Primary Group delay valid flag for channel 2.
DEL2A[25:0] Primary Group delay for channel 2.
EBIT3A Primary Group delay valid flag for channel 3.
DEL3A[25:0] Primary Group delay for channel 3.
EBIT4A Primary Group delay valid flag for channel 4.
DEL4A[25:0] Primary Group delay for channel 4.
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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