Keysight M9502A, Руководство пользователя

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92 Keysight M9502A/M9505A AXIe Chassis User Guide
Features and Functions LVDS Local Bus
LVDS Local Bus
The M9502A and M9505A chassis backplane provides a local bus with 62
differential signaling pairs between each pair of adjacent instrument physical
slots. This bus is the Low Voltage Differential Signaling or LVDS bus.
Availability of these signal lines to any module will depend on vendor
implementation of the Zone 2 connectors and related commands to manage
signaling on the local bus. See
“Interconnection” on page 90 for a look at these
connectors.
The chassis provides these local bus pairs on Zone 2 backplane connectors
P20-P24. Most instrument modules will load connector P20 to access the trigger
and timing bus, and will load connector J23 in order to utilize the AXIe base and
data fabrics. Connector J23 provides the first 22 local bus pairs from backplane
to module.
Modules designed to take maximum advantage of the AXIe local bus will load
additional connectors (P24, P21) and expand the local bus up to 42 or 62 signals
to each adjacent module slot. If P24 (or P24 and P21) are loaded on your
module, likely the vendor is utilizing the local bus.
Check with the module vendor for any instrument in your AXIe chassis to
determine if it utilizes the AXIe local bus and what functionality that feature
provides you.
Electronic Keying (E-Keying)
Electronic keying is one of several capabilities AXIe inherits from the
AdvancedTCA architecture. Like ATCA, AXIe promotes a fabric independent (also
known as fabric-agnostic) backplane with respect to local bus connectivity.
Each module plugged into a chassis may provide various communication
protocols and hardware signaling that connect to pins on the backplane that link
adjacent modules together. In general, the backplane itself does not provide
internal buffering, so a link connection between two adjacent modules is simply
a wired connection, either configured point to point or tied together on a
common bus. This allows different modules in the system to establish their own
link protocols provided a connection path exists.
This flexibility frees the chassis configuration from dictating signal levels and
protocols involved with any particular link. However, this flexibility presents a
challenge: how to know whether the endpoints of a link are compatible or not.
If you have modules in your system that are E-Keying compatible, refer to the
documentation provided with your modules for detailed installation information.