Sc Express Considerations; Sc Express Clock And Trigger Signals; Pxie_Clk100; Pxi_Clk10 - National Instruments SC Express PXIe-4309 User Manual

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SC Express Considerations

This chapter details the clock and trigger functionality available through the PXI Express
chassis.

SC Express Clock and Trigger Signals

PXIe_CLK100

PXIe_CLK100 is a common, low-skew 100 MHz reference clock used for synchronization of
multiple modules in a PXI Express measurement or control system. The PXIe backplane is
responsible for generating PXIe_CLK100 independently to each peripheral slot in a PXI Express
chassis. For more information, refer to the PXI Express Specification at
.
www.pxisa.org

PXI_CLK10

PXI_CLK10 is a common, low-skew 10 MHz reference clock for synchronization of multiple
modules in a PXI measurement or control system. The PXI backplane is responsible for
generating PXI_CLK10 independently to each peripheral slot in a PXI chassis. In PXIe chassis,
the PXI_CLK10 signal is in phase with PXIe_CLK100.
PXI_CLK10 cannot be used as a reference clock for SC Express modules.
Note

PXI Triggers

A PXI/PXIe chassis provides eight bused trigger lines to each module in a system. Triggers may
be passed from one module to another, allowing precisely timed responses to asynchronous
external events that are being monitored or controlled. Triggers can be used to synchronize the
operation of several different PXI peripheral modules.
In a PXI chassis with more than eight slots, the PXI trigger lines may be divided into multiple
independent buses. Refer to the documentation for your chassis for details.

PXI_STAR Trigger

In a PXI Express system, the Star Trigger bus implements a dedicated trigger line between the
system timing slot and the other peripheral slots. The Star Trigger can be used to synchronize
multiple modules or to share a common trigger signal among modules.
A system timing controller can be installed in the system timing slot to provide trigger signals
to other peripheral modules. Systems that do not require this functionality can install any
standard peripheral module in this system timing slot.
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