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PXI Express Considerations
This chapter details the clock and trigger functionality available through the PXI Express chassis
for the NI PXIe-4357.
NI SC Express Clock and Trigger Signals
PXIe_CLK100
PXIe_CLK100 is a common low-skew 100 MHz reference clock for synchronization of multiple
modules in a PXI Express measurement or control system. The PXI Express 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
.
PXIe_SYNC100
PXIe_SYNC100 is a common low-skew 10 MHz reference clock with a 10% duty cycle for
synchronization of multiple modules in a PXI Express measurement or control system. This
signal is used to accurately synchronize modules using PXIe_CLK100 along with those using
PXI_CLK10. The PXI Express backplane is responsible for generating PXIe_SYNC100
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.
Note
PXI_CLK10 cannot be used as a reference clock for SC Express modules.
PXI Triggers
A PXI 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.
On SC Express modules, the eight PXI trigger signals are synonymous with RTSI <0..7>.
