![](http://datasheet.mmic.net.cn/130000/TVP5150PBS_datasheet_5023402/TVP5150PBS_51.png)
Functional Description
45
May 2006
SLES043A
3.22.48 VBI FIFO Read Data Register
Address
B0h
7
6
5
4
3
2
1
0
FIFO read data
This address is provided to access VBI data in the FIFO through the host port. All forms of teletext data come
directly from the FIFO, while all other forms of VBI data can be programmed to come from the registers or from
the FIFO. Current status of the FIFO can be found at address C6h and the number of bytes in the FIFO is
located at address C7h. If the host port is to be used to read data from the FIFO, then the output formatter
must be disabled at address CDh bit 0. The format used for the VBI FIFO is shown in Section 3.12.
3.22.49 Teletext Filter and Mask Registers
Address
B1h–BAh
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]):
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 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 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, then 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 0s are programmed in the mask bits, then 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