
Postparser Operation
8-19
8.2.14 Auxiliary Data FIFO Operation
The Auxiliary Data FIFO is used to store certain header parameters
required by the system controller or host. The FIFO operates as a
128-byte-deep circular buffer. The various registers associated with the
Auxiliary Data FIFO are listed in
Table 8.12
and described in the text
following. More complete descriptions can be found at the page
references shown in the table.
When the Postparser writes the first byte of auxiliary data into the Aux
Data FIFO, the Aux/User Data FIFO Ready Interrupt is set. When the
Postparser detects the First Slice Start Code in the bitstream, it sets the
First Slice Start Code Detect Interrupt bit. When set and not masked,
either bit causes INTRn to be asserted to the host. The host should
respond by reading Registers 0 through 4 to determine the cause of the
interrupt.
If the host detects that the AUX/User Data FIFO Interrupt is set, it should
read the Aux Data FIFO Status bits and the User Data FIFO Status bits
to determine which FIFO to read. The status code meanings are shown
in
Table 8.13
.
Table 8.12
Aux Data FIFO Registers
Register
Bit(s)
R/W
Name
Page
Ref.
0
1
R
Aux/User Data FIFO Ready Interrupt
4-2
W
Aux/User Data FIFO Ready Interrupt Mask
0
2
R
First Slice Start Code Detect Interrupt
4-3
W
First Slice Start Code Detect Interrupt Mask
64
0
W
Reset Aux Data FIFO
4-17
[1:0]
R
Aux Data FIFO Status [1:0]
4-17
[4:2]
R
Aux Data Layer ID [2:0]
4-18
67
[7:0]
R
Aux Data FIFO Output [7:0]
4-19