L64777 A LSI Logic Corporation, L64777 A Datasheet - Page 9

• Manufacturer Part Number: L64777 A
• Description: Communications, DVB QAM Modulator
• Manufacturer: LSI Logic Corporation

Control Interface
Serial Microprocessor Interface
Input Synchronization
An external CPU uses the L64777 serial control interface to control and
setup the programmable parameters of the chip. This interface is a slave
type only, connected to the same serial bus as the LSI Logic L64724.
A bidirectional microprocessor interface allows write and confidence
read-back of internal registers. No interaction during operation is required
with the microprocessor, but all registers must be configured after a
RESET to guarantee proper operation of the device. A default setup that
requires no microprocessor download is built in for 64 QAM.
The L64777 transport interface reads the data stream from the transport
source, identifies the position of the synchronization bytes, and strips off
invalid data. The transport interface can operate in either Parallel or
Serial mode.
The L64777 can synchronize the transport interface in two ways. In both
modes, it works synchronously with ICLK and reads all signals, including
input data, on the raising edge of ICLK.
L64777 DVB QAM Modulator
In external synchronization mode, the transport interface specifies
the position of the external sync byte by asserting FSTARTIN HIGH
during sync byte input. In serial mode, the interface must assert the
signal HIGH during the first bit (MSB) of the input stream.
In internal synchronization mode, the L64777 does not require a
block start indication and finds the position of the programmed sync
byte automatically.
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