Table 4-16: Parallel Data Output Format (Continued)
DATA-THROUGH MODE**
20bit DEMULTIPLEXED SD
10bit MULTIPLEXED SD
DATA
DATA
DATA
13.5MHz
27MHz
HIGH
LOW
HIGH
HIGH
LOW
LOW
LOW
LOW
FORCED
LOW
20bit DEMULTIPLEXED HD
10bit MULTIPLEXED HD
DATA
DATA
DATA
74.25 or
74.25/
1.001MHz
HIGH
LOW
LOW
LOW
LOW
LOW
LOW
LOW
FORCED
LOW
148.5 or
148.5/
1.001MHz
*NOTE1: Recall that SD/HD, SMPTE_BYPASS, and DVB_ASI are input control pins in slave mode to be set by the application layer, but
the SD/HD and SMPTE_BYPASS pinsare output status signals set by the device in Master mode.
**NOTE 2: Data-Through mode is only available in Slave mode Data Through Mode on page 39.
4.12 GSPI Host Interface
The GSPI, or Gennum Serial Peripheral Interface, is a 4-wire interface provided to allow
the host to enable additional features of the device and/or to provide additional status
information through configuration registers in the GS1559.
The GSPI comprises a Serial Data Input signal SDIN, Serial Data Output signal SDOUT,
an active low Chip Select CS, and a Burst Clock SCLK. The Burst Clock must have a duty
cycle between 40% and 60%.
Because these pins are shared with the JTAG interface port, an additional control signal
pin JTAG/HOST is provided. When JTAG/HOST is LOW, the GSPI interface is enabled.
When operating in GSPI mode, the SCLK, SDIN, and CS signals are provided by the Host
Interface. The SDOUT pin is a high-impedance output allowing multiple devices to be
connected in parallel and selected via the CS input. The interface is illustrated in
Figure 4-9.
All read or write access to the GS1559 is initiated and terminated by the Host Processor.
Each access always begins with a 16-bit Command Word on SDIN indicating the address
of the register of interest. This is followed by a 16-bit Data Word on SDIN in Write mode,
or a 16-bit Data Word on SDOUT in Read mode.
Application Host
SCLK
GS1559
SCLK
SDIN
SDOUT
CS
CS
SDIN
SDOUT
Figure 4-9: Gennum Serial Peripheral Interface (GSPI)
GS1559 HD-LINX™ II Multi-Rate Deserializer with
Loop-Through Cable Driver
Data Sheet
60 of 71
30572 - 8
July 2008
GENNUM [ GENNUM CORPORATION ]
