6

Special Operation Functions:

Electrical and optical high speed data “wrap” functions are enabled to assist with local host or remote diagnostic and

optimization sequences. Optical data wrap (OWRAP) takes a received optical signal through a CDR jitter cleanup and

retransmits it optically out. Electrical data wrap (EWRAP) takes an incoming electrical signal through a CDR jitter cleanup

and retransmits it electrically out. An optional pass-through function is available to transmit outbound the wrapped

information, controlled through i2c commands.

The electrical SFP input stage (TD +/-) has been enhanced with features to allow host control and optimization of the

transceiver’s input equalization settings. The host can then select, in situ, the most appropriate SFP setting for a given

interconnect scenario.

The SFP electrical output stage (RD+/-) has been enhanced with variable output emphasis features to allow host control

and optimization of the receiver’s output settings. The host can then select, in situ, the most appropriate SFP setting for

a given interconnect scenario. To assist with optimizing the receiver output setting, the user can have data transmitted

by the SFP to a host ASIC by using EWRAP to loop back host generated traffic or can use a remotely generated optical

signal as a data source for SFP and interconnect training.

Table 2. Rate Select Function

Function

State

Explanation

Rx Rate Select

RS(0)

High

Receive Rate Select HIGH engages the internal Rx CDR. The CDR will look for valid 16GFC traffic and

lock within 500us when found. Due to differences in coding, this CDR will not be able to lock on valid

8GFC or 4GFC traffic.

Low

Receive Rate Select LOW bypasses the internal Rx CDR. This is intended for use only with 8GFC and

4GFC traffic. When set low, the SFP behaves like a legacy SFP.

Tx Rate Select

RS(1)

High

Transmit Rate Select HIGH engages the internal Tx CDR. The CDR will look for valid 16GFC traffic and

lock within 500us when found. Due to differences in coding, this CDR will not be able to lock on valid

8GFC or 4GFC traffic.

Low

Transmit Rate Select LOW bypasses the internal Tx CDR. This is intended for use only with 8GFC and

4GFC traffic. When set low, the SFP behaves like a legacy SFP.

Note: During Fibre Channel Link Speed Negotiation sequences, the host will control Tx Rate and Rx Rate inputs separately to accomplish link initial-

ization. Once speed negotiation is complete, it is expected both Tx Rate and Rx Rate will be placed in the same state by the host.

Figure 2c.

SFP Tx Variable Input Electrical EQ (i2c controlled)

Figure 2d.

SFP Rx Variable Output Electrical Emphasis (i2c controlled)

Figure 2a. OWRAP Function

ality (i2c controlled)

Figure 2b.

Rx Vout &

Emphasis

Tx EQ

Rx

CDR

Tx

CDR

µ

controller

Post

Amp

Laser

Driver

Pre

Amp

Rx Vout &

Emphasis

Tx EQ

Rx

CDR

Tx

CDR

µcontroller

Post

Amp

Laser

Driver

Pre

Amp

Rx Vout &

Emphasis

Tx EQ

Rx

CDR

Tx

CDR

µcontroller

Post

Amp

Laser

Driver

Pre

Amp

i2c setting

Rx Vout &

Emphasis

Tx EQ

Rx

CDR

Tx

CDR

µcontroller

Post

Amp

Laser

Driver

Pre

Amp

i2c setting