SLES209E
–
NOVEMBER 2007
–
REVISED OCTOBER 2011
At power-up the host interface is required to program the VDP-configuration RAM (VDP-CRAM) contents
with the lookup table (see
This is done through port address C3h. Each read from or
write to this address auto increments an internal counter to the next RAM location. To access the
VDP-CRAM, the line mode registers (D0h to FCh) must be programmed with FFh to avoid a conflict with
the internal microprocessor and the VDP in both writing and reading. Full field mode must also be
disabled.
Available VBI lines are from line 6 to line 27 of both field 1 and field 2. Each line can be any VBI mode.
Output data is available either through the VBI-FIFO (B0h) or through dedicated registers at 90h to AFh,
both of which are available through the I
2
C port.
3.9
VBI FIFO and Ancillary Data in Video Stream
Sliced VBI data can be output as ancillary data in the video stream in the ITU-R BT.656 mode. VBI data is
output during the horizontal blanking period following the line from which the data was retrieved.
shows the header format and sequence of the ancillary data inserted into the video stream. This format is
also used to store any VBI data into the FIFO. The size of FIFO is 512 bytes. Therefore, the FIFO can
store up to 11 lines of teletext data with the NTSC NABTS standard.
Table 3-2. Ancillary Data Format and Sequence
BYTE NO.
0
1
2
3
4
5
6
7
8
9
10
11
...
D7
(MSB)
0
1
1
NEP
NEP
NEP
D6
0
1
1
EP
EP
EP
D5
0
1
1
0
F5
N5
D4
0
1
1
1
F4
N4
Data
error
D3
0
1
1
0
F3
N3
D2
0
1
1
DID2
F2
N2
D1
0
1
1
DID1
F1
N1
D0
(LSB)
0
1
1
DID0
F0
N0
DESCRIPTION
Ancillary data preamble
Data ID (DID)
Secondary data ID (SDID)
Number of 32-bit data (NN)
Internal data ID0 (IDID0)
Video line [7:0]
0
0
0
Match 1 Match 2
Video line [9:8]
Internal data ID1 (IDID1)
Data byte
Data byte
Data byte
Data byte
...
Data byte
Data byte
First word
1. Data
2. Data
3. Data
4. Data
...
m–1. Data
m. Data
RSVD
CS[5:0]
0
0
0
0
0
0
0
Check sum
Fill byte
N
th
word
4(N+2)–1
1
EP:
NEP:
DID:
Even parity for D0–D5
Negated even parity
91h: Sliced data of VBI lines of first field
53h: Sliced data of line 24 to end of first field
55h: Sliced data of VBI lines of second field
97h: Sliced data of line 24 to end of second field
SDID:
NN:
IDID0:
14
This field holds the data format taken from the line mode register of the corresponding line.
Number of Dwords beginning with byte 8 through 4(N+2). This value is the number of
Dwords where each Dword is 4 bytes.
Transaction video line number [7:0]
Copyright
©
2007–2011, Texas Instruments Incorporated
Functional Description
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