Enhanced Mode Operations
VCM-DAS-3 Reference Manual
35
Enhanced Mode Operations
The VCM-DAS-3 must be in enhanced mode to perform enhanced mode operations.
R
EADING
DAC
D
ATA
Reading a DAC using the Read DAC operation does not cause the DAC to be updated, as reading
the DACALL0 register does. Performing a Read DAC operation loads the DAC voltage code in
the ENDATHI and ENDATLO registers. To read the voltage of a DAC:
1.
Perform a Read DAC operation by writing 8h to the CTRL field of the ENCTRL register
at I/O port 0x30A, combined with the channel number in the SEL field of the same
register.
2.
Read the ENDATHI register and then the ENDATLO register. The 12 bits of the output
voltage code are offset toward the MSB, as shown below.
ENDATHI MSB (Read) 0309h
7
6
5
4
3
2
1
0
D11
D10
D9
D8
D7
D6
D5
D4
ENDATLO LSB (Read) 0308h
7
6
5
4
3
2
1
0
D3
D2
D1
D0
0
0
0
0
R
EADING THE
S
PAN OF A
C
HANNEL
To read the span of a channel:
1.
Perform a Read Span operation by writing 9h to the CTRL field of the ENCTRL register
at I/O port 0x30A, combined with the channel number in the SEL field of the same
register.
2.
Read the span code from bits 3-0 of the ENDATLO register at I/O port 0x308, as shown
below.
ENDATLO LSB (Read) 0308h
7
6
5
4
3
2
1
0
–
–
–
–
D3
D2
D1
D0
