
L64005 MPEG-2 Audio/Video Decoder Technical Manual
3-5
Final Rev F
Copyright 1996 by LSI Logic Corporation. All rights reserved.
SCLKI
Serial Clock
Input
SCLKI is used to latch a single bit of coded MPEG data
into the device on the rising edge. SCLKI may be asyn-
chronous to the device clock. The value on SERI is
clocked into the L64005 video channel buffer on the rising
edge of SCLKI if VVALID is asserted HIGH and the
device is in serial stream mode. LSI Logic recommends
using a free running SCLKI for data input in serial mode.
LSI Logic does not recommend using a gated SCLKI.
The value on SERI is clocked into the L64005 audio
channel buffer on the rising edge of SCLKI if AVALID is
HIGH and the device is in serial stream mode. Operation
when both AVALID and VVALID are asserted HIGH is
undened. SCLKI is periodic at the channel rate. This pin
is unused in parallel stream mode, but must toggle during
reset.
SERI
Serial Data Input
Input
SERI is a serial data input for coded MPEG data. SERI
is latched on the next rising edge of SCLKI when the
device is in serial stream mode. SERI is unused in paral-
lel stream mode. The state of VVALID or AVALID directs
the data to either the video or the audio channel buffer.
VREQ
Video Transfer Request
Output
When VREQ is asserted LOW, it indicates that the
decoder is ready to receive a new byte of coded video
data.VREQ is also used as the request for DMA transfer
to DRAM in parallel mode The decoder is considered
ready when both the interface is ready and space is avail-
able in the video channel buffer. If this is not true, VREQ
will not be asserted. The maximum transfer rate over this
interface is 27 Mbits/s in serial mode, and 40 Mbits/s in
parallel mode.
VVALID
Video Data Valid
Input
In serial stream mode, the serial clock writes the next bit
of video data into the chip if VVALID is asserted HIGH.
In parallel stream mode, the rising edge of VVALID writes
the next byte of video data into the chip.VVALID is also
used as the parallel strobe for DMA transfers into DRAM.