Digital Routing And Clock Generation; Clock Routing - National Instruments PXI-6238 User Manual

Digital Routing and Clock
Generation
The digital routing circuitry has the following three main functions.
•
•
•

Clock Routing

Figure 10-1 shows the clock routing circuitry of an M Series device.
Onboard
80 MHz
Oscillator
External
Reference
RTSI <0..7>
Clock
PXI_CLK10
PXI_STAR
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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 M 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 M Series device.
÷ 8
PLL
÷
Figure 10-1. M Series Clock Routing Circuitry
10-1
10
10 MHz RefClk
(To RTSI <0..7>
Output Selectors)
80 MHz Timebase
20 MHz Timebase
4
÷
200 100 kHz Timebase
NI 6238/6239 User Manual