GS4911B Datasheet, PDF (77/119 Pages) Gennum Corporation – HD/SD/Graphics Clock and Timing Generator with GENLOCK

Application Host
SCLK
CS1
SDOUT
GS4911B/GS4910B
SCLK
CS
SDIN
SDOUT
CS2
SDIN
GS4911B/GS4910B
SCLK
CS
SDIN
SDOUT
Figure 3-14: GSPI Application Interface Connection
All read or write access to the GS4911B/GS4910B 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.
3.12.1 Command Word Description
The command word consists of 16 bits transmitted MSB first and includes a read/write
bit, an Auto-Increment bit and a 12-bit address. Figure 3-15 shows the command word
format and bit configurations.
Command words are clocked into the GS4911B/GS4910B on the rising edge of the serial
clock, SCLK, which operates in a burst fashion.
When the Auto-Increment bit is set LOW, each command word must be followed by
only one data word to ensure proper operation. If the Auto-Increment bit is set HIGH,
the following data word will be written into the address specified in the command word,
and subsequent data words will be written into incremental addresses. This facilitates
multiple address writes without sending a command word for each data word.
Auto-Increment may be used for both read and write access.
MSB
LSB
R/W RSV RSV ^AutoInc A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
RSV = Reserved. Must be set to zero. R/W: Read command when R/W = 1
Write command when R/W = 0
Figure 3-15: Command Word Format
GS4911B/GS4910B HD/SD/Graphics Clock and Timing
Generator with GENLOCK
Data Sheet
36655 - 5
June 2009
77 of 119