Chapter 2 Analog Input Timing/Control©National Instruments Corporation2-97DAQ-STC Technical Reference ManualThe numbers in parentheses indicate edge-gating mode, depending on which mode youspecify in AI_START1_Edge, AI_START2_Edge, AI_START_Edge, or AI_STOP_Edge.2.7.8 Trigger OutputYou can output the internal triggers to the board through the PFI or RTSI interface. Thissection lists the propagation delays for the triggers when you configure the triggers for outputto the board.2.7.8.1 START1 and START2 TriggersYou can output the START1 trigger on the PFI output PFI0/AI_START1 or on any RTSIoutput. You can output the START2 trigger on the PFI output PFI1/AI_START2 or on anyRTSI output. Timing for START1 and START2 depends on whether you select synchronousmode or asynchronous mode, using AI_START1_Sync and AI_START2_Sync.Synchronous ModeWhen you select synchronous mode for START1 or START2, the timing depends on whetheryou select internal CONVERT or external CONVERT, using AI_CONVERT_Source_Select.In the internal CONVERT mode, the inactive edge of the SI2 source that recognizes theexternal trigger generates the output. Figure 2-27 shows the propagation delays for START1.Figure 2-28 shows the propagation delays for START2.Tstrt START pulsewidth (edge mode) 6 —Th_strt START hold from CONVERT_SRC(level mode)4 —Ts_stop STOP setup to CONVERT_SRC 31 (34) —Tstop STOP pulsewidth (edge mode) 6 —Th_stop STOP hold from CONVERT_SRC(level mode)4 —All timing values are in nanoseconds.Table 2-5. External Analog Input Timing (Continued)Name Description Minimum Maximum
