
L64105 Overview
1-3
Figure 1.2
L64105 Decoder Block Diagram
The read and write FIFOs are used to give the host access to the
external SDRAM. The read/write paths are still through registers. The
interface supports direct read/write, DMA transfers using an external
DMA controller, and block moves within SDRAM. The byte enable logic
converts host byte writes to 8-byte words for the write FIFO and 64-bit
internal bus and vice versa. The byte enable logic also performs byte
switching for little endian hosts.
The Channel Interface accepts byte-wide MPEG streams and a clock.
The interface synchronizes to and preparses the incoming stream by
stripping system headers and storing them in a dedicated buffer area in
SDRAM. The interface also separates the audio and video streams and
stores them in dedicated buffer areas in SDRAM. A buffer controller
maintains the read and write pointers for the dedicated buffers.
The Memory Interface includes byte enable logic and an address
converter. The recommended SDRAM is 16 bits wide, so the byte enable
logic performs the conversion between the SDRAM bus and the 8-byte
wide internal bus of the L64105. The host and internal microcontroller of
Host
Interface
Microcontroller
DCK (£ 9 MHz)
L64105 Decoder
Video
Decoder
Video
Interface
SDRAM Buffers and
Frame Stores
Audio
Decoder
Video to
NTSC/PAL
Encoder
I/O
Control
Audio
and
Clocks
to DAC
Oversampling
Clock In
S/P DIF
Out
Status
and
Control
CH_DATA[7:0]
Data
and
Address
Buses
Memory
Interface
Channel
Interface
SYSCLK
(27 MHz)
64-bit
Address Bus
Data Bus