Interfaces and Connectors
EBX-22 Reference Manual
51
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
XTERNAL
C
ONNECTIONS
Single-ended analog voltages are applied to connector J15 as shown in the following table.
Table 24: Analog Input Pinout
J15
Pin
Signal
Function
CBR-4004
Connector
CBR-4004
Pin (Signal)
31
ADCH0
Analog Input Channel 0
J8
1 (IO25)
32
ADCH1
Analog Input Channel 1
Analog
2 (IO26)
33
ADCH2
Analog Input Channel 2
3 (IO27)
34
ADCH3
Analog Input Channel 3
4 (I028)
35 GND
Ground
5 (GND4)
36
ADCH4
Analog Input Channel 4
J9
1 (IO29)
37
ADCH5
Analog Input Channel 5
Analog
2 (IO30)
38
ADCH6
Analog Input Channel 6
3 (IO31)
39
ADCH7
Analog Input Channel 7
4 (IO32)
40 GND
Ground
5 (GND4)
C
ALIBRATION
There are no calibration adjustments. Calibration, if desired, is accomplished by mathematical
transformation in software.
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