L64105 LSI Logic Corporation, L64105 Datasheet - Page 267

• Manufacturer Part Number: L64105
• Description: Mpeg-2 Audio/video Decoder
• Manufacturer: LSI Logic Corporation

8.3.1 Channel Start/Reset and Status Bits
The channel start command causes the Preparser to start accepting data
from the external channel interface device. For details on how to control
the location of the video channel in SDRAM memory and on selecting
the proper stream ID, the reader is referred to Chapter 6, “Channel
Interface,” and
command is issued and the Video ES Channel Buffer has filled to a
sufficient level, the host decode start command is issued. This signals
the decoder to begin decoding the bitstream and reconstructing the
picture in the frame store memory, which is allocated in SDRAM. The
start of video decode can also be achieved by using the Autostart Video
function. The following sections explain the operation of the various host
registers required to program the functions mentioned previously. The
process is illustrated with the help of a time line that shows how these
operations should be sequenced in time.
After power-up or chip reset, the channel is in the reset state. At this
time, the various start and end addresses of the channel are assigned
in SDRAM by writing to the appropriate registers (See
“Channel Interface,”
Start/Reset bit (bit 0 of Register 7,
start. This results in the Video ES Channel Buffer receiving the MPEG
elementary video bitstream from the external channel interface. The host
can monitor the status of the channel by reading the Channel
Start/Reset/Status bit in Register 7. The host can stop the channel by
clearing the Channel Start/Reset/Status.
Video Decoder Pacing
Note:
The Channel Status bit is updated when the decoder
acknowledges the channel stop command and not when
the host writes a 0 to the bit. The Channel Start/Reset bit
is checked regularly by the decoder.
Chapter 7, “Memory Interface.”
for more details.). Writing a 1 to the Channel
page
4-11) causes the channel to
After the channel start
Chapter 6,
8-25