Chapter 5
Theory of Operation and Register-Level Programming
5-6
©
National Instruments Corporation
Figure 5-3.
AMUX-64T Channel Address Mapping
To perform an A/D conversion on a single AMUX-64T channel, perform
the following programming steps:
1.
Select an analog input channel on the AMUX-64T by writing the
appropriate channel address bits to digital I/O port A (bits 0 through 3
of the Digital Output Register).
2.
Write to the External Strobe Register to load the channel address into
the AMUX-64T scanning counter.
3.
Write to the MA<3..0> bits in the Mux-Gain Register to select the
four-to-one multiplexer on the AMUX-64T you want to address.
Now follow the normal procedure for performing a single A/D conversion
or multiple A/D conversions on a single input channel of the MIO board
with one exception—the bits MA<3..0> of the Mux-Gain Register must
correspond to the middle four bits of your channel address shown in
Figure 5-3.
8-Bit Channel Address
7
6
5
4
3
2
1
0
CA7
CA6
CA5
CA4
CA3
CA2
CA1
CA0
ADO0
ADO1
MA0
MA1
MA2
MA3
ADO2
ADO3
Select AMUX-64T
Channel <0..3>
Select AMUX-64T
Multiplexer <0..15>
Select AMUX-64T
Board <0..3>
