Xycom XVME 590, Manual

Page: 54 / 102

XVME-500/590 Manual
February, 1988
D6
D O
0 1 1 0 1 0 0 0
Gain Factor
of 2
Enables the
Register to
Write* to
Gain RAM
Selects Channel
8 for gain
programming
Figure 3-3. Select Channel 8 For Gain
Example 2: Reading and Initiating a Conversion at Channel 15
By writing OFH to the module base + 85H (in the Random Channel mode), the Gain
RAM
for channel 15 can be read (the gain is read at bits D6 & D7). When reading
base + 85H, D5 will always be zero because it is grounded. In addition, a
conversion is initiated on channel 15 (See Figure 3-4).
D O
X X 0 0
1
1 1 1
1 I
Gain Factor’
Enables
Selects Channel
is read here
Register for 15 for a gain
Convert Mode Read /Convert
Figure 3-4. Conversion at Channel 15
3.3.4
A/D Data Input Register (Base + word location 86H)
The
A/D
converter produces digital data which corresponds to the applied analog
input from a specified channel. This digital data is accessible to the ‘Host’
processor at the 16-bit A/D Data Input Register (base + 86H). A word register (16-
b i t ) i s u s e d t o p r o v i d e t h e s p a c e n e c e s s a r y f o r 12-bit resolution.
Digital
information in this register may be read in either a byte or word format.
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