GS1582 Datasheet, PDF (78/114 Pages) Gennum Corporation – Multi-Rate Serializer with Cable Driver, Audio Multiplexer and ClockCleaner™

GS1582 Data Sheet
4.13.1 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 4-27 shows the
command word format and bit configurations.
Command words are clocked into the GS1582 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 0 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
RSV = Reserved. Must be set to zero. R/W: Read command when R/W = 1
Write command when R/W = 0
Figure 4-27: Command Word
MSB
LSB
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Figure 4-28: Data Word
4.13.2 Data Read and Write Timing
Read and write mode timing for the GSPI interface is shown in Figure 4-29 and
Figure 4-30 respectively. The timing parameters are defined in Table 4-41.
When several devices are connected to the GSPI chain, only one CS must be set
LOW during a read sequence.
During the write sequence, all command and subsequent data words are looped
through from SDIN to SDOUT. When several devices are connected to the GSPI
chain, data can be written simultaneously to all the devices that have CS set LOW.
40117 - 1 November 2007
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