GS1675 Datasheet, PDF (24/37 Pages) Gennum Corporation – Differential inputs and outputs

3.14.11 Writing to a Single Device in the Chain
The following example shows how to write to a single device in a chain:
CS
MOSI ^{CommandN [15:0]}
Chain Position = N
DataN [15:0]
MISO
Data High 32xN cycles
Data High 32 cycles
CommandN’ [15:0] DataN [15:0]
Chain Position = N (N = 0 for first device in chain)
Figure 3-13: Daisy Chain Write to a Single Device
1. The command is issued to Chain Position N.
2. 32xN cycles are required to shift the command through N devices. The device at
chain position N executes the command.
3. 32 additional cycles are needed to complete the communication.
3.14.12 Reading from all Devices
To read from all devices in the chain, a Read command is issued for each device
consecutively. After each command, the data is held HIGH for 16 cycles. Once a device
recognizes that it is being talked to, it will output data from the register requested. A
clock needs to be applied to cycle the output data through all devices in the chain.
CS
SDI
SDO
Command 2
(Chain Position = 2)
Data HIGH for
16 cycles
Command 1
(Chain Position = 1)
Data HIGH for
16 cycles
Command 0
(Chain Position = 0)
Data HIGH for
16 cycles
CS
SDI
Data held
HIGH for 32x3
cycles
SDO Command2’
Data2
Command1’
Data1
Figure 3-14: Daisy Chain Read
Command0’
Data0
GS1675 SD/HD SDI Reclocker
Data Sheet
54174 - 1
June 2011
24 of 37