Chapter 4
General-Purpose Counter/Timer
DAQ-STC Technical Reference Manual
4-48
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National Instruments Corporation
G
i_Source_Polarity
i = 0
bit: 15
type: Write
in: G0_Input_Select_Register
address: 36
i = 1
bit: 15
type: Write
in: G1_Input_Select_Register
address: 37
This bit selects the active edge of the general-purpose counter i source:
0: Rising edge.
1: Falling edge.
Related bitfields: Gi_Source_Select.
G
i_Source_Select
i = 0
bits: <2..6>
type: Write
in: G0_Input_Select_Register
address: 36
i = 1
bits: <2..6>
type: Write
in: G1_Input_Select_Register
address: 37
This bitfield selects the general-purpose counter i source:
0: The internal signal G_IN_TIMEBASE1.
1-10: PFI<0..9>.
11-17: RTSI_TRIGGER<0..6>.
18: The internal signal IN_TIMEBASE2.
19: The G_TC signal from the other general-purpose counter.
31: Logic low.
G
i_Stale_Data_St
i = 0
bit: 6
type: Read
in: G_Status_Register
address: 4
i = 1
bit: 7
type: Read
in: G_Status_Register
address: 4
This bit indicates that no source edge was detected between two adjacent relevant gate edges.
This bit is used for noncumulative event counting and period measurement.
G
i_Stop_Mode
i = 0
bits: <5..6>
type: Write
in: G0_Mode_Register
address: 26
i = 1
bits: <5..6>
type: Write
in: G1_Mode_Register
address: 27
This bit selects the condition on which the counter will stop:
0: Stop on gate condition.
1: Stop on gate condition or at the first TC, whichever comes first.
2: Stop by gate condition or at the second TC, whichever comes first.
3: Reserved.
Notice that, regardless of this bitfield setting, you can always use the software disarm
command, Gi_Disarm, to stop the counter. The gate condition that stops the counter is
determined by Gi_Gating_Mode (in case of level gating) or by a combination of
Gi_Gating_Mode and Gi_Trigger_Mode_For_Edge_Gate (in case of edge gating). Selections
1 and 2 are valid only if Gi_Trigger_Mode_For_Edge_Gate is set to 2 (no hardware limit on
this). Related bitfields: Gi_Disarm, Gi_Gating_Mode, Gi_Trigger_Mode_For_Edge_Gate.