HMP8170 Datasheet, PDF (11/33 Pages) Intersil Corporation – NTSC/PAL Video Encoder

HMP8170, HMP8171, HMP8172, HMP8173
TABLE 8. BT.656 ANCILLARY DATA FORMAT FOR WIDESCREEN SIGNALLING DATA
PIXEL INPUT
P15
P14
P13
P12
P11
P10
Preamble 1
0
0
0
0
0
0
Preamble 2
1
1
1
1
1
1
Preamble 3
1
1
1
1
1
1
Data ID
ep#
ep
1
1
0
0
Data Block Number
ep#
ep
0
0
0
0
Data Word Count
ep#
ep
0
0
0
0
WSS Data Nibble 3
ep#
ep
0
0
0
0
WSS Data Nibble 2
ep#
ep
0
0
bit 11
bit 10
WSS Data Nibble 1
ep#
ep
0
0
bit 7
bit 6
WSS Data Nibble 0
ep#
ep
0
0
bit 3
bit 2
WSS CRC Nibble 1
ep#
ep
0
0
0
0
WSS CRC Nibble 0
ep#
ep
0
0
bit 3
bit 2
Reserved
ep#
ep
0
0
0
0
Reserved
ep#
ep
0
0
0
0
CRC
P14#
X
X
X
X
X
NOTES:
The even parity (EP and EP#) bits are ignored.
Line = Data Register Select: 0 = Line 20; 1 = 283.
The WSS CRC data bits are ignored during PAL operation but must be included in the transfer.
X = Don’t Care.
P9
0
1
1
1
0
1
bit 13
bit 9
bit 5
bit 1
bit 5
bit 1
0
0
X
P8
0
1
1
Line
1
0
bit 12
bit 8
bit 4
bit 0
bit 4
bit 0
0
0
X
TABLE 9. WIDESCREEN SIGNALLING MODES
WSS REGISTERS
WSS
ENABLE BITS
OUTPUT LINE(S)
283A, 283B,
CRC283
20A, 20B,
CRC20
00
None
Ignored
Ignored
01
20 (NTSC)
17 (M PAL)
23 (Other PAL)
Ignored
WSS Data
10
283 (NTSC)
280 (M PAL)
336 (Other PAL)
WSS Data
Ignored
11
20, 283 (NTSC)
17, 280 (M PAL)
23, 336 (Other PAL)
WSS Data
WSS Data
NOTE: The CRC registers are always ignored during PAL operation.
WRITE STATUS BIT
283
Always 1
Always 1
20
Always 1
0 = Loaded
1 = Output
0 = Loaded
1 = Output
Always 1
0 = Loaded
1 = Output
0 = Loaded
1 = Output
Teletext
The HMP817x supports ITU-R BT.653 625-line and 525-line
teletext system B and C generation. WST (World System
Teletext) is the same as BT.653 system B. NABTS (North
American Broadcast Teletext Specification) is the same as
BT.653 525-line system C. NABTS is also used to transmit
Intel Intercast information.
During the teletext encoding, the line’s pixel inputs are
ignored. The teletext information includes a 16-bit clock
synchronization code; the HMP817x automatically
generates it.
The teletext output level depends on the video format. For
system B teletext, the output level is 66 IRE for a logic 1 and 0
IRE for a logic 0. All transitions between levels are controlled to
have a raised-cosine shape with a rise or fall time of 200ns. For
system C teletext, the output level is 70 IRE for a logic 1 and 0
IRE for a logic 0. All transitions between levels are controlled to
have a raised-cosine shape with a rise or fall time of 200ns.
The HMP817x generates teletext output on any scan line
that includes teletext data in that line’s BT.656 ancillary data.
The encoder must receive the ancillary data before the SAV
sequence in order to output the teletext data. Table 10 shows
the BT.656 ancillary data format for loading the teletext data
registers.
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