Keysight Technologies U4301 User Manual page 25

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Keysight U4301 PCIe Gen3 Analyzer User's Guide
The Link Type refers to the type of link that you want to create between the U4301A/B module and
DUT. You can select the 1 Unidirectional up to x16 link type if you want the U4301A/B module to
probe and capture data in only one direction (upstream or downstream). In the Unidirectional link
type, the U4301A/B module can support a unidirectional link with upto 16 channels in the same
direction. You can select the 1 Bidirectional up to x8 link type if you want the same U4301A/B
module to probe and capture data in both directions (upstream as well as downstream). In the
bidirectional link type, the U4301A/B module can support one bidirectional link with upto eight
channels for each direction. When you select the bidirectional link type, two sub-links are created
for the two directions. You can set the link attributes such as clock source, master lane, and lane
ordering separately for these two sub-links. These attributes are available in the Link Naming and
Lane Setup section.
The following screen displays the sub-links of a x8 bidirectional link. These sub-links have been
renamed on the basis of the direction these represent.
If you have installed multiple U4301A/B modules in the chassis, all these modules are listed in
the Module section of the tab. You need to select the link type individually for these modules.
Select the link width.
By default, the link width is set to the maximum link width available to the U4301 module at
which it can capture data. This maximum link width available is based on the module's license
options installed and the link type (Unidirectional/Bidirectional) that you selected. If you select
the Link Type as 1 Bidirectional upto x8, then you can select the Link Width from x1 to x8. The
x16 option is disabled in this case because a U4301 module can probe and capture data in both
directions with upto eight channels in each direction.
You can set the link width for the U4301 module in either of the following two ways:
a Set the link width manually using the Link Width listbox and make sure that you match the set
link width with the negotiated link width of the transmitter and receiver. Otherwise, the data
capture will not happen. For instance, if the negotiated link is at x8, then the module's link
width should be set to x8, otherwise the capture will not happen.
b Retain the maximum link width set by default in the Link Width field and make sure that the
Auto checkbox displayed with the Link Width field is selected. By doing so, you enable the auto
link width detection feature. As a result, the U4301 module automatically detects link width
during initial link up as well as link width changes during up/down configurations and
accordingly sets its link width based on these changes as seen in the captured data. This
allows data capture as per the changing link width.
Specifying the Connection Setup 3
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