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CL-CS3712-33QC-A

Integrated AVI/ATAPI DVD Drive Manager

Cirrus Logic 

PRELIMINARY DRAFT

Functional Decriptions

Functional Decriptions

This section overviews the main functional blocks of the CL-CS3712 Integrated AVI/

ATAPI DVD Drive Manager, and is divided into the following sub-sections:

• "Decoder" on page 2

• "Data Channel" on page 4

• "Servo Channel" on page 6

Decoder

DVD Mode

The CL-CS3712 contains a highly automated DVD/CD decoder that takes EFM data from

the Analog Front and Digital PRML read channel and transform this data through a series

of operations into user data and sends it to the Host controller.

The sequence of operation is as follows:

The high level firmware sets up the decoder through the UP control interface. The

decoder is controlled through a register set. The high level FW sets up the mode of

operation (CD or DVD), the buffer manager and the host interface. The external SDRAM

buffer is controlled through a set of address pointers programmed by the FW. This

address pointers controls the data flow from the DISC, to and fro to the ECC Block and

the HOST.

The actual data that is written on the DVD DISC is a transformed version of the user data

and follows the DVD Physical Specification.

To understand the decoder flow the transformation process needs to be understood,

which is beyond the scope of this document. In summary the user data is organized in

sectors (2048 bytes). The transformation process involves adding ID (Sector #) and other

information such as copy protection etc. to the data, Scrambling the data, ECC encoding,

splitting the data into recording frames , EFM modulation and creation of EFMP frames

with unique sync patterns inserted for EFMP frame identification.

The function of the decoder is to take this transformed data and convert back into the

user format.

Once the FW sets the start transfer control bit(s) in the decoder, the Decoder starts

processing the data from the Read Channel. The data is in the EFMP format (Eight to

Fourteen Modulation Plus) as defined in the DVD Physical Specification. The first step is

to synchronize and align the data on the EFMP frame boundaries by detecting unique

sync patterns that are embedded in the EFMP data stream. Once the data is aligned on

the EFMP frame boundary it is de-serialized into 16-bit symbols, and than demodulated

into 8 bits of data according to the EFMP modulation standard.

The next step is to determine the right starting point to start the transfer of data into the

buffer. The FW will program the Target Header or ID information. Once the incoming data

ID matches the programmed ID, data transfer to the Buffer starts. The data transfer

DS588PP1 - rev 0.4 April 11, 2002

© Copyright 2002 Cirrus Logic Inc.

CONFIDENTIAL

www.cirrus.com

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