GS1503 Gennum Corporation, GS1503 Datasheet - Page 56

• Manufacturer Part Number: GS1503
• Description: HD Embedded Audio Codec
• Manufacturer: Gennum Corporation

2.9 ARBITRARY DATA PACKETS
The GS1503 can demultiplex arbitrary data packets
according to SMPTE 291M. Typically, arbitrary data packets
consist of linear time code (LTC), vertical interval time code
(VITC) or other user data, which is multiplexed once per
video field. The GS1503 has two modes in which arbitrary
2.9.1 Arbitrary Data Demultiplexing in External Pin Mode
This is the default mode for demultiplexing arbitrary data
packets. The GS1503 will set the PKTEN external pin HIGH
before arbitrary data will be output. Two VCLK cycles after
PKTEN goes HIGH, arbitrary data is output on the PKT[7:0]
bus. See Figure 42 for timing.
PKT[7:0]
Arbitrary
PKTEN
Packet
VCLK
MSB
LSB
Contents available in Host Interface registers
2 CLKs
Y/C b / C r [19:0]
Fig. 42 Arbitrary Data Packet Output Timing Diagram
Fig. 41 Arbitrary Data Packet Structure
VIN[19:0]
56
GS1503
data can be demultiplexed from the Luma channel of the
video data stream. A maximum of 255 user data words can
be demultiplexed. Figure 41 shows the structure of the
arbitrary data packet.
The following arbitrary data is output on the PKT[7:0] bus:
Data ID (DID), Secondary Data ID (SDID), Data Count (DC)
and User Data Words (UDW: up to a maximum of 255
words).
Parity bit
User Data Words
Not b8
PKT[7:0]
Arbitrary Data
PKTEN
Arbitrary Data Output Enable
Arbitrary Data
2 CLKs
15879 - 1