Chapter 2
Analog Input Timing/Control
DAQ-STC Technical Reference Manual
2-102
©
National Instruments Corporation
External CONVERT Mode
In the external CONVERT mode, the START and SCAN_IN_PROG outputs are generated by
the active edge of the CONVERT source that recognizes START. If you set
AI_Trigger_Length to 0, both edges of the START pulse are generated by the same edge of
the CONVERT source. If you set AI_Trigger_Length to 1, the START pulse is stretched.
Figure 2-34 shows the propagation delays for START and SCAN_IN_PROG in the external
CONVERT mode. The deassertion delay for PFI7/AI_START is indicated for the case where
AI_Trigger_Length is set to 0.
Figure 2-34.
START Delays, External CONVERT
Name
Description
Minimum
Maximum
Tpfi
CONVERT_SRC to PFI output (START)
14
48
Tpfin
CONVERT_SRC to PFI output (START)
deassert
23
77
Tbrd
CONVERT_SRC to BRD output (START)
15
53
Tscan
CONVERT_SRC to SCAN_IN_PROG
15
54
Tspfi
CONVERT_SRC to PFI output
(SCAN_IN_PROG)
15
54
Tsbrd
CONVERT_SRC to BRD output
(SCAN_IN_PROG)
17
58
All timing values are in nanoseconds.
CONVERT_SRC
START
(START)
(START)
(SCAN_IN_PROG)
(SCAN_IN_PROG)
PFI7/AI_START
RTSI_BRD<2..3>
SCAN_IN_PROG
Tpfi
Tbrd
Tscan
PFI7/AI_START
Tspfi
RTSI_BRD<2..3>
Tsbrd
Tpfin