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Chapter 4 Register Map and Descriptions
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National Instruments Corporation 4-39 AT-MIO-16X User Manual
Writing to the channel configuration memory must be preceded with a
strobe to the CONFIGMEMCLR Register. After the channel
configuration memory is set up, the first value must be preloaded by
accessing the CONFIGMEMLD Register. Writing to the
CONFIGMEM Register following a CONFIGMEMCLR automatically
sequences into the memory list for multiple-channel configuration
values. Writing can continue until the end of the channel configuration
list is reached, or the memory becomes full. After the final write to the
channel configuration memory, the CONFIGMEMLD Register should
be strobed to load the first channel configuration value. At this point,
the channel configuration memory is primed and does not need to be
accessed again until a new channel configuration sequence is desired.
Conversions, either by EXTCONV* or by Counter 3 of the Am9513A
Counter/Timer, automatically sequence through the channel
configuration memory as programmed. When the end of the channel
configuration memory is detected, it is automatically reset to the first
value in the list. Strobing the DAQ Clear Register also resets the
channel configuration memory to the first value in the list without
destroying existing channel configuration values. A strobe of the
CONFIGMEMLD Register is still necessary to load the first value in
the memory.
Table 4-9. Input Configuration
Input Mode
Bit Map Effect
CHAN_CAL
CHAN_SE
CHAN_AIS
PGIA (+) PGIA (–)
DIFF 0 0 X Channels 0 to 7 Channels 8 to 15
RSE 0 1 0 Channels 0 to 15 AI GND
NRSE 0 1 1 Channels 0 to 15 AI SENSE
Offset Calibration 1 X 0 AI GND AI GND
Gain Calibration 1 X 1 Internal +5 V
ref
AI GND
Note:
X indicates a
don’t care
bit.