GS2962 Datasheet, PDF (62/82 Pages) Gennum Corporation – Integrated Narrow-Bandwidth PLL

Application Host
SCLK
CS1
SDOUT
GS2962
SCLK
CS
SDIN
SDOUT
CS2
SDIN
GS2962
SCLK
CS
SDIN
SDOUT
Figure 4-21: GSPI Application Interface Connection
All read or write access to the GS2962 is initiated and terminated by the application host
processor. Each access always begins with a Command/Address Word followed by a
data read to or written from the GS2962.
4.11.1 Command Word Description
The Command Word consists of a 16-bit word transmitted MSB first and contains a
read/write bit, an Auto-Increment bit and a 12-bit address. Figure 4-22 shows the
command word format and bit configurations.
Command Words are clocked into the GS2962 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 from the
previous Data Word. This facilitates multiple address writes without sending a
Command Word for each Data Word.
NOTE: All registers can be written to through single address access or through the
Auto-increment feature. However, the LSB of the video registers cannot be read through
single address read-back. Single address read-back will return a zero value for the LSB.
If auto-increment is used to read back the values from at least two registers, the LSB
value read will always be correct. Therefore, for register read-back, it is recommended
that auto-increment be used and that at least two registers be read back at a time.
MSB
LSB
R/W RSV
RSV AutoInc A11 A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
Figure 4-22: Command Word Format
GS2962 3G/HD/SD-SDI Serializer with Complete
SMPTE Video Support
Data Sheet
48005 - 7
October 2010
62 of 82