Datasheet

Functional Description
50
May 2006SLES043A
3.22.55 VDP Status Register
Address C6h
7 6 5 4 3 2 1 0
FIFO full error FIFO empty TTX available CC field 1 available CC field 2 available WSS available VPS available VITC available
The VDP status register indicates whether data is available in either the FIFO or data registers, and status
information about the FIFO. Reading data from the corresponding register does not clear the status flags
automatically. These flags are only reset by writing a 1 to the respective bit. However, bit 6 is updated
automatically.
FIFO full error:
0 = No FIFO full error
1 = FIFO was full during a write to FIFO.
The FIFO full error flag is set when the current line of VBI data can not enter the FIFO. For example, if the FIFO
has only 10 bytes left and teletext is the current VBI line, the FIFO full error flag is set, but no data is written
because the entire teletext line will not fit. However, if the next VBI line is closed caption requiring only 2 bytes
of data plus the header, this goes into the FIFO. Even if the full error flag is set.
FIFO empty:
0 = FIFO is not empty.
1 = FIFO is empty.
TTX available:
0 = Teletext data is not available.
1 = Teletext data is available.
CC field 1 available:
0 = Closed caption data from field 1 is not available.
1 = Closed caption data from field 1 is available.
CC field 2 available:
0 = Closed caption data from field 2 is not available.
1 = Closed caption data from field 2 is available.
WSS available:
0 = WSS data is not available.
1 = WSS data is available.
VPS available:
0 = VPS data is not available.
1 = VPS data is available.
VITC available:
0 = VITC data is not available.
1 = VITC data is available.
3.22.56 FIFO Word Count Register
Address C7h
7 6 5 4 3 2 1 0
Number of words