Register Descriptions Chapter 4
SCXI-1120 User Manual 4-4 © National Instruments Corporation
Bit Name Description (continued)
5 RTEMP Read Temperature – This bit determines whether the
selected channel output or the MTEMP signal is driven
onto the MCH0± pins of the rear signal connector. If
RTEMP is cleared to 0, the selected channel output is used
as the module output. If RTEMP is set to 1, the MTEMP
signal is used as the module output. The module output
will only be driven when FOUTEN* is cleared to 0, or
SCANCON is active (low) while SCANCONEN* is
cleared.
4 RSVD Reserved – This bit should always be written to 0.
3 SCANCLKEN Scan Clock Enable – This bit determines whether
MUXCOUNTER will increment on each clock signal (the
clock source is determined by CLKSELECT), or keep its
loaded value. If SCANCLKEN is set to 1,
MUXCOUNTER will be clocked during scans. If
SCANCLKEN is cleared to 0, MUXCOUNTER will not be
clocked.
2 SCANCONEN Scan Control Enable – This bit, when set to 1, enables the
SCANCON signal.
1 AB0EN Analog Bus 0 Enable – This bit determines whether Analog
Bus 0 on the SCXIbus drives MCH0 on the rear signal
connector. If AB0EN is cleared to 0, Analog Bus 0 doesnot
drive MCH0. If AB0EN is set to 1, Analog Bus 0 + drives
MCH0+ through a buffer and a Analog Bus 0 - is connected
to MCH0-.
0 FOUTEN* Forced Output Enable – This bit determines whether the
module will drive the MCH0± pins on the rear signal
connector with either the selected channel output or the
MTEMP signal, depending on the state of RTEMP. If
FOUTEN* is cleared to 0, the MCH0± pins will be driven
through a buffer by the selected channel output or the
MTEMP line. If FOUTEN* is set to 1, the MCH0± pins
will not be driven by the selected channel output or
MTEMP, unless SCANCON is active (low) and the
SCANCONEN bit is cleared. If the selected channel output
or MTEMP is driving the output buffer, it will drive Analog
Bus 0 if AB0EN is set. If nothing is driving the output
buffer, the SCXI-1120 output will saturate.