80 Mhz Source Mode; Other Internal Source Mode - National Instruments NI 6238 User Manual

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Otherwise, the mode depends on the signal that drives Counter n Source.
Table 7-6 describes the conditions for each mode.
Table 7-6. Synchronization Mode Conditions
Duplicate
Count
Prevention
Enabled Measurement
Yes Any
No Position
Measurement
No Any
No All Except
Position
Measurement
No All Except
Position
Measurement

80 MHz Source Mode

In 80 MHz source mode, the device synchronizes signals on the rising edge
of the source, and counts on the following rising edge of the source, as
shown in Figure 7-34.
Source
Synchronize
Figure 7-34. 80 MHz Source Mode

Other Internal Source Mode

In other internal source mode, the device synchronizes signals on the
falling edge of the source, and counts on the following rising edge of the
source, as shown in Figure 7-35.
Signal Driving
Type of Counter n
Source
Any
Any
80 MHz
Timebase
20 MHz
Timebase, 100
kHz Timebase,
or PXI_CLK10
Any Other
Signal (such as
PFI or RTSI)
7-39
Chapter 7 Counters
Synchronization
Mode
80 MHz Source
80 MHz Source
80 MHz Source
Other Internal
Source
External Source
Count
NI 6238/6239 User Manual