National Instruments AT-MIO-16X - Manual (Page 71)

Chapter 3 Theory of Operation
© National Instruments Corporation 3-5 AT-MIO-16X User Manual
selected for DMA transfer. These DMA channels are selectable from
one of the registers in the AT-MIO-16X register set.
Analog Input and Data Acquisition Circuitry
The AT-MIO-16X handles 16 channels of analog input with
software-programmable configuration and 16-bit A/D conversion. In
addition, the AT-MIO-16X contains data acquisition configuration for
automatic timing of multiple A/D conversions and includes advanced
options such as external triggering, gating, and clocking. Figure 3-3
shows a block diagram of the analog input and data acquisition
circuitry.
Figure 3-3. Analog Input and Data Acquisition Circuitry Block Diagram
EEPROM
Calibration
Constants
ACH0
ACH1
ACH2
ACH3
ACH4
ACH5
ACH6
ACH7
ACH8
ACH9
ACH10
ACH11
ACH12
ACH13
ACH14
SCANCLK
SCAN CLK
External Convert
External Timer Trigger Data
Acquisition
Timing
Channel
Configu-
ration
Memory
Counter/Timer
Signals
CONFIG CLK
Data
CONFIGMEMWR
CONV AVAIL
16
A/D
Data ADC
FIFO
+
– Unipolar/
Bipolar
Selection
Mux Mode
Selection
Switches
MUX0OUT
MUX
0
MUX
1
MUX1OUT
AI SENSE
EXTCONV
PC I/O Channel
EXTTRIG*
In Of
f
Out Of
f
2
Gain
PGIA
GAIN1
GAIN0
MA3
MA2
MA1
MA0
GAIN2
Calibration
AIS/AIG
SE/DIFF
Convert
LASTCH
Data
A/D RD
8
Reference
ADC
Calibration
DACs
16
2
I/O Connector