Chapter 3
Hardware Overview
©
National Instruments Corporation
3-7
NI PCI-1588 User Manual
Timing System Performance
The NI PCI-1588 can generate or input a 1 Hz pulse per second signal on
any PFI or RTSI terminal. You can set up this signal to transition on the
seconds boundary of the 1588 system time. You can then use this signal to
analyze system performance by connecting two or more pulse per second
signals to an oscilloscope and measuring the latency between them.
Adjustments can be made to account for deterministic latency. Refer to the
NI-Sync API Reference Help
for more information. The NI PCI-1588 can
also timestamp an incoming pulse per second signal. The NI PCI-1588 will
timestamp the externally generated pulse per second with its internal 1588
system time. By comparing this timestamp with the nearest seconds
boundary, you can quickly determine the synchronization performance.
I/O Considerations
Using the Ethernet Port
The NI PCI-1588 provides one standard RJ-45 connection for
Ethernet communication. This port auto negotiates to the best possible
speed—10 Mbps or 100 Mbps. The Ethernet port is auto-MDI capable,
which means crossover cabling is not necessary when connecting the
NI PCI-1588 to another network card. The NI PCI-1588 senses whether a
crossed connection is needed and performs the action internally. The
Ethernet port also allows for full duplex operation, so traffic can be sent and
received at the same time.
Using Front Panel PFIs as Outputs
The front panel PFI output signals use +3.3 V signaling for high-impedance
loads. You can use the PFI terminals to generate events and low speed
(
≤
1 Mhz) clock signals. PFI output signals are suitable for driving most
LEDs. To ensure proper signaling for fast edge rate signals, ensure that the
system terminates to 50
Ω
on the receiving end. Cabling should also be
50
Ω
impedance. In a 50
Ω
environment, the PFI terminals will output less
than +3.3 V in the high state. See the
Specifications
appendix for more
information. Refer to the
NI-Sync User Manual
for information on how
to set up the PFI lines for output.
Caution
Do not attempt to drive signals into PFI terminals set up as outputs. Doing so can
damage the NI PCI-1588.
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