GS4901B_09 Datasheet, PDF (63/102 Pages) Gennum Corporation – SD Clock and Timing Generator with GENLOCK

Serial
Video
Input
Video Data
GS1559
Deserializer ^PCLK
FPGA
vin[19:0]
pclk
PCLK1
GS49xxB
/512
aclk128a
HD AUDIO
DEMUX CORE
PCLK1
GS49xxB
/512
aclk128b
aclkdiv2b
aclkdiv2a
aclk64a
wclka
aout1_2
aout3_4
aclk64b
wclkb
aout5_6
aout7_8
Figure 3-10: Audio Clock Block Diagram for HD Demux Operation
3.10 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 GS4901B/GS4900B and/or to provide
additional status information through configuration registers in the device.
The GSPI comprises a serial data input signal, SDIN, a 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
application interface. The SDOUT pin is a non-clocked loop-through of SDIN and may
be connected to the SDIN pin of another device, allowing multiple devices to be
connected to the GSPI chain. The interface is illustrated in Figure 3-11.
GS4901B/GS4900B SD Clock and Timing Generator
with GENLOCK
Data Sheet
37703 - 4
December 2009
63 of 102