8
L64020 Single Chip DVD Decoder
Host Interface
A stand-alone, dedicated host interface allows the user to program a
variety of options and monitor the operation of the L64020. In addition,
through this port you can read user data that is present in the data
channel and read errors agged by the L64020. The device does not
maintain unread user data indenitely. The host interface includes a FIFO
to which no more data can be written once the FIFO becomes full.
Subsequent data will be lost. The system controller must read data
transmitted in the user data records of the MPEG bitstream, even if that
data is subsequently used to control some aspect of the video display
subsystem. The controller must read this data, then write it to the L64020
internal state registers, if necessary. The host interface also allows you
to read and write data into the memory for OSD and channel buffer
access.
Channel Interface
The L64020 includes an independent parallel interface for direct
connection to upstream error correction devices. The interface uses
simple signal handshaking for compressed stream transfer to the
decoder.
The L64020's channel interface handles the incoming coded data, which
is assumed to be an MPEG-2 compliant bitstream, and provides error
detection and reporting. The channel interface detects data in the
bitstream that does not meet MPEG-2 or Dolby Digital syntax or
grammar rules and can ag the data for exception processing. Hardware
error handling includes error masking and the application of concealment
vectors in video. Audio error concealment includes muting on errors and
searching for error-free frames. The channel interface ags gross errors
in the bitstream that are due to channel buffer overrun or underrun or to
nonconformance in the bitstream. The error agging is done so the errors
can be masked in the display or in the audio output. To handle gross
errors, you can program an external microcontroller with an error
recovery mechanism.
Memory Interface
The L64020 supports direct connection to commercial SDRAM for use
as frame stores, channel buffers, and overlay memory. The L64020 uses
frame stores for intermediate frame reconstruction and display, separate