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ni579x Host Align 2 (Clock-Driven Logic)

Last Modified: September 10, 2016

Aligns the synchronization targets. You must align the synchronization targets before synchronizing a signal.

ni579x Host Align and ni579x FPGA Align provide the same quality of synchronization, but differ in requirements and versatility of operation. When using ni579x FPGA Align, the clock-driven loop (CDL) rate containing this node must be an integer multiple of the sync.cptr.Reference Clock rate, and the CDL clock must have a fixed phase relationship to the Reference Clock.

Each target performs its alignment independently, so ni579x FPGA Align does not require an FPGA I/O line. You can also use ni579x FPGA Align without host interaction. ni579x FPGA Align has 100% repeatability if-and-only-if the target-to-target phase relationship is low and does not change. When using ni579x Host Align, the CDL rate may be arbitrary, but still must have a fixed phase relationship to the other targets. The CPTR period may also be arbitrary. This alignment process is coordinated by the host, and requires an FPGA I/O line for orchestration. ni579x FPGA Align has 100% repeatability; if the hardware configuration remains constant, the level of synchronization remains constant as well.



Identifies the Synchronization instance. Sync.resources is obtained from ni579x Create.



The start signal. When using ni579x FPGA Align, the sync.meas.Reference Clock must be the same clock that the target's FPGA Clock is locked to. This is commonly PXI_Clk10.


sync.meas.FPGA I/O

The FPGA I/O line that starts the alignment process. The FPGA I/O line used is usually a PXI trigger line.


For large NI chassis, ensure the PXI trigger line is routed to all bus segments that have targets participating in synchronization.


sync.resources 2

The synchronization instance is obtained from the create node.

Where This Node Can Run:

Desktop OS: none

FPGA: All devices

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