GS1675 Datasheet, PDF (15/37 Pages) Gennum Corporation – Differential inputs and outputs

Power up
270Mb/s
1485Mb/s
*Note: the search algorithm does not necessarily begin with 270Mb/s.
Figure 3-2: GS1675 Automatic Mode Search Algorithm
In MANUAL mode, the SS[1:0] registers become read or write accessible, and the data
rate can be programmed. In this mode, the search algorithm is disabled and the GS1675's
PLL will only lock to the data rate selected in accordance with Table 3-4.
Table 3-4: Data Rate Indication/Selection Bit Pattern
SS[1:0]
0
1
2
3
Data Rate (Mb/s)
Reserved for 3G migration
270
1485 or 1485/1.001
Reserved for 3G migration
3.10 SD/HD Indication
The SD/HD signal indicates the output data rate of the device and can be connected to
the SD/HD input pin of the GS1678 and GS1679.
When this signal is HIGH, the data rate is 270Mb/s. This signal is LOW for all other data
rates.
This signal is also LOW when the device is operating in bypass mode (Auto-bypass and
User-bypass).
The SD/HD signal is LOW when the device is not locked.
3.11 Bypass Mode
In bypass mode, the GS1675 passes the data at the inputs, directly to the output. There
are two register bits that control the bypass function: BYPASS and AUTOBYPASS.
GS1675 SD/HD SDI Reclocker
Data Sheet
54174 - 1
June 2011
15 of 37