Chapter 2
Analog Input Timing/Control
©
National Instruments Corporation
2-75
DAQ-STC Technical Reference Manual
AI_START_Pulse
bit: 2
type: Strobe
in: AI_Command_2_Register
address: 4
Setting this bit to 1 sends a START trigger to the counters if the START software strobe is
selected (AI_START_Select is set to 18). This bit is cleared automatically. Related bitfields:
AI_START_Select.
AI_START_Second_Irq_Enable
bit: 3
type: Write
in: Second_Irq_A_Enable_Register
address: 74
This bit enables the START interrupt in the secondary interrupt bank:
0: Disabled.
1: Enabled.
The START interrupt is generated on valid START triggers received by the DAQ-STC. A
valid START trigger is one that is received while the SC counter is enabled to count.
AI_START_Select
bits: <0..4>
type: Write
in: AI_START_STOP_Select_Register
address: 62
This bit selects the START trigger:
0: The internal signal SI_TC.
1–10: PFI<0..9>.
11–17: RTSI_TRIGGER<0..6>.
18: Bitfield AI_START_Pulse.
19: The internal signal G_OUT from general-purpose counter 0.
31: Logic low.
When you set this bit to 0, the DAQ-STC is in the internal START mode. When you select
any other signal as the START trigger, the DAQ-STC is in the external START mode.
Related bitfields: AI_START_Pulse.
AI_START_St
bit: 5
type: Read
in: AI_Status_1_Register
address: 2
This bit indicates that a valid START trigger has been received by the AITM:
0: No.
1: Yes.
A valid START trigger is one that is received while the SC counter is enabled to count. You
can clear this bit by setting AI_START_Interrupt_Ack to 1. Refer to Table 8-2,
, for more information.