Analog Input; External Connections; Calibration - VersaLogic EBX-22 Reference Manual

Analog Input

The EBX-22 analog input interface uses a 12-bit A/D converter that accepts up to eight single-
ended input signals. The converter features 500 kilo-samples per second (kSPS) conversion time,
with an input range of 0 to +4.095V with 4096 steps at 0.001V each. A/D input capacitance is 33
pF. The absolute maximum input voltage is 4.395V (4.095V + 0.300V) and minimum input
voltage -0.300V.
The EBX-22 A/D converter can be controlled three different ways, using an ADC state machine,
the SPI interface, or the analog input "bit bang" registers. This section describes all three A/D
conversion methods. The ADC state machine method constantly scans the analog chip for inputs.
Warning!
Application of analog voltages greater than +4.395V can physically damage the
converter.
E C
XTERNAL ONNECTIONS
Single-ended analog voltages are applied to connector J15 as shown in the following table.
J15
Pin
31
32
33
34
35
36
37
38
39
40
C
ALIBRATION
There are no calibration adjustments. Calibration, if desired, is accomplished by mathematical
transformation in software.
EBX-22 Reference Manual
Table 24: Analog Input Pinout
Signal Function
ADCH0 Analog Input Channel 0
ADCH1 Analog Input Channel 1
ADCH2 Analog Input Channel 2
ADCH3 Analog Input Channel 3
GND Ground
ADCH4 Analog Input Channel 4
ADCH5 Analog Input Channel 5
ADCH6 Analog Input Channel 6
ADCH7 Analog Input Channel 7
GND Ground
Interfaces and Connectors
CBR-4004 CBR-4004
Connector Pin (Signal)
J8 1 (IO25)
Analog 2 (IO26)
3 (IO27)
4 (I028)
5 (GND4)
J9 1 (IO29)
Analog 2 (IO30)
3 (IO31)
4 (IO32)
5 (GND4)
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