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National Instruments Corporation
9-1
9
Digital Routing and Clock
Generation
The digital routing circuitry has the following main functions:
•
Manages the flow of data between the bus interface and the
acquisition/generation sub-systems (analog input, analog output,
digital I/O, and the counters). The digital routing circuitry uses FIFOs
(if present) in each sub-system to ensure efficient data movement.
•
Routes timing and control signals. The acquisition/generation
sub-systems use these signals to manage acquisitions and generations.
These signals can come from the following sources:
–
Your S Series device
–
Other devices in your system through RTSI
–
User input through the PFI terminals
–
User input through the PXI_STAR terminal
•
Routes and generates the main clock signals for the S Series device.
Clock Routing
Figure 9-1 shows the clock routing circuitry of an S Series device.
Figure 9-1.
S Series Clock Routing Circuitry
RTSI <0..7>
Onboard
80 MHz
Oscillator
External
Reference
Clock
(To RTSI <0..7>
Output Selectors)
10 MHz RefClk
PLL
÷
4
÷
200
÷
8
PXI_CLK10
PXI_STAR
80 MHz Timebase
100 kHz Timebase
20 MHz Timebase
