Chapter 3
Analog Output Timing/Control
DAQ-STC Technical Reference Manual
3-110
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National Instruments Corporation
AO_IN_TIMEBASE1
Internal Timebase for the Analog Output
Module—AO_IN_TIMEBASE1 can be selected to be the same as
OSC, or it can be OSC divided by two. Related bitfields:
AO_Source_Divide_By_2.
AO_OUT_TIMEBASE
AO Output Clock—This signal times the output circuitry for analog
output. Related bitfields: AO_OUTPUT_Divide_By_2.
BC_CE
BC Count Enable—This signal enables and disables the BC counter.
Refer to Figure 3-39 for the BC_CE logic equations.
BC_CLK
BC Clock—The BC clock signal is the actual clock for the BC
counter and the BC control logic. When the counter is not armed,
BC_CLK is the write strobe for AO_Command_1_Register so that
the counter can be loaded using the load command. When the counter
is armed, BC_CLK is the same as BC_SRC.
BC_DISARM
BC Disarm—This signal, which is generated by the BC control
circuit, disarms the BC counter by asynchronously clearing
AO_BC_Arm.
BC_HOLD
BC Hold—This signal controls the BC save register.
If BC_HOLD = 0, the BC save register tracks the BC counter output.
If BC_HOLD = 1, the BC save register latches the BC counter output.
Related bitfields: AO_BC_Save_Trace.
BC_LOAD
BC Load—This signal pulses to load the value from the selected BC
load register into the BC counter. Related bitfields: AO_BC_Load.
BC_LOAD_SRC
BC Load Source—This signal determines which load register, A or
B, the BC counter will use on the next reload. The initial BC load
source is set using AO_BC_Initial_Load_Source. The BC control
logic updates BC_LOAD_SRC while the DAQ-STC is counting. The
current load source depends on the counter state and the selected
reload mode. Related bitfields: AO_BC_Initial_Load_Source,
AO_BC_Next_Load_Source_St, AO_BC_Reload_Mode.
BC_SRC
BC Source—The BC source is the timebase for the buffer (BC)
counter and update (UC) counter. If an internally generated UPDATE
is used, the BC source is the same signal as the UI_SRC. If an
externally generated UPDATE is used, the UPDATE clock itself
serves as the BC source. The external trigger and gate inputs which
are not generated synchronous to the BC source outside of the timer
can and should be synchronized to the BC source inside of the timer.
Table 3-6.
Internal Signals (Continued)
Signal
Description
