Datasheet

Table Of Contents
ADV7188
Rev. A | Page 68 of 112
VPS/PDC/UTC/Gemstar
The readback registers for VPS, PDC, and UTC are shared.
Gemstar is a high data rate standard and therefore is available
only through the ancillary stream. For evaluation purposes, any
one line of Gemstar is available through the I
2
C registers sharing
the same register space as PDC, UTC, and VPS. Therefore, only
one of the following standards can be read through the I
2
C at a
time: VPS, PDC, UTC, or Gemstar.
To identify the data that should be made available in the I
2
C
registers, the user must program I2C_GS_VPS_PDC_UTC [1:0]
(Address 0x9C, user sub map).
I2C_GS_VPS_PDC_UTC (VDP) [1:0], Address 0x9C [6:5],
User Sub Map
These bits specify which standard result is available for I
2
C
readback.
Table 82. I2C_GS_VPS_PDC_UTC [1:0] Function
I2C_GS_VPS_PDC_UTC [1:0] Description
00 (default) Gemstar 1×/2×
01 VPS
10 PDC
11 UTC
GS_PDC_VPS_UTC_CLEAR, GS/PDC/VPS/UTC Clear,
Address 0x78 [4], User Sub Map, Write Only, Self-Clearing
1—Reinitializes the GS/PDC/VPS/UTC data readback registers.
GS_PDC_VPS_UTC_AVL, GS/PDC/VPS/UTC Available,
Address 0x78 [4], User Sub Map, Read Only
0—GS, PDC, VPS, or UTC data was not detected.
1—GS, PDC, VPS, or UTC data was detected.
VDP_GS_VPS_PDC_UTC Readback Registers,
Addresses 0x84 to 0x90, User Sub Map
See Table 83 .
VPS
The VPS data bits are biphase decoded by the VDP. The
decoded data is available in both the ancillary stream and in
the I
2
C readback registers. VPS decoded data is available in the
VDP_GS_VPS_PDC_UTC_0 to VDP_VPS_PDC_UTC_12
registers (Addresses 0x84 to 0x90, user sub map). The
GS_VPS_PDC_UTC_AVL bit is set if the user had programmed
I2C_GS_VPS_PDC_UTC to 01, as explained in
Table 82 .
Gemstar
The Gemstar decoded data is available in the ancillary stream,
and any one line of Gemstar is available in I
2
C registers for
evaluation purposes. To obtain the Gemstar results in the I
2
C
registers, the user must program I2C_GS_VPS_PDC_UTC to
00, as explained in
Table 82.
VDP supports autodetection of Gemstar, distinguishing between
Gemstar 1× and Gemstar 2×, and decodes data accordingly. For
this autodetection mode to operate correctly, the user must set
the AUTO_DETECT_GS_TYPE I
2
C bit (Register 0x61, user
sub map) and program the decoder to decode Gemstar 2× on
the required lines through line programming. The type of
Gemstar decoding can be determined by observing the
GS_DATA_TYPE bit (Register 0x78, user sub map).
AUTO_DETECT_GS_TYPE, Address 0x61 [4],
User Sub Map
0 (default)—Disables autodetection of Gemstar type.
1—Enables autodetection of Gemstar type.
GS_DATA_TYPE, Address 0x78 [5],
User Sub Map, Read Only
This bit identifies the decoded Gemstar data type.
0—Gemstar 1× mode is detected. Read two data bytes from 0x84.
1—Gemstar 2× mode is detected. Read four data bytes from 0x84.
The Gemstar data that is available in the I
2
C register may be
from any line of the input video on which Gemstar was
decoded. To read the Gemstar data on a particular video line,
the user should use the manual configuration as described in
Table 67 and Table 68 and enable Gemstar decoding only on the
required line.