Datasheet
TVP5150AM1
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SLES209E–NOVEMBER 2007– REVISED OCTOBER 2011
3.21.60 Teletext Filter and Mask Registers
Address B1h–BAh
Default 00h
Address 7 6 5 4 3 2 1 0
B1h Filter 1 mask 1 Filter 1 pattern 1
B2h Filter 1 mask 2 Filter 1 pattern 2
B3h Filter 1 mask 3 Filter 1 pattern 3
B4h Filter 1 mask 4 Filter 1 pattern 4
B5h Filter 1 mask 5 Filter 1 pattern 5
B6h Filter 2 mask 1 Filter 2 pattern 1
B7h Filter 2 mask 2 Filter 2 pattern 2
B8h Filter 2 mask 3 Filter 2 pattern 3
B9h Filter 2 mask 4 Filter 2 pattern 4
BAh Filter 2 mask 5 Filter 2 pattern 5
For an NABTS system, the packet prefix consists of five bytes. Each byte contains four data bits (D[3:0])
interlaced with four Hamming protection bits (H[3:0]):
7 6 5 4 3 2 1 0
D[3] H[3] D[2] H[2] D[1] H[1] D[0] H[0]
Only the data portion D[3:0] from each byte is applied to a teletext filter function with the corresponding
pattern bits P[3:0] and mask bits M[3:0]. Hamming protection bits are ignored by the filter.
For a WST system (PAL or NTSC), the packet prefix consists of two bytes so that two patterns are used.
Patterns 3, 4, and 5 are ignored.
The mask bits enable filtering using the corresponding bit in the pattern register. For example, a 1 in the
LSB of mask 1 means that the filter module must compare the LSB of nibble 1 in the pattern register to
the first data bit on the transaction. If these match, a true result is returned. A 0 in a bit of mask 1 means
that the filter module must ignore that data bit of the transaction. If all zeros are programmed in the mask
bits, the filter matches all patterns returning a true result (default 00h).
Pattern and mask for each byte and filter are referred as <1,2><P,M><1,2,3,4,5>, where:
<1,2> identifies the filter 1 or 2
<P,M> identifies the pattern or mask
<1,2,3,4,5> identifies the byte number
Copyright © 2007–2011, Texas Instruments Incorporated Functional Description 63
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