NI roboRIO User Manual
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© National Instruments
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15
Figure 15.
NI roboRIO AO Circuitry
DIO, PWM, and Relay Lines
The NI roboRIO provides the following DIO lines:
•
3.3 V general-purpose DIO lines on the MXP
•
3.3 V digital lines on the DIO, I
2
C, and SPI ports
•
5 V digital lines on the PWM and Relay ports.
DIO <9..0> on the DIO port, CS <3..0> on the SPI port, and DIO <13..0> on the MXP all have
40 k
Ω
pullup resistors to 3.3 V, as shown in Figure 16.
Figure 16.
DIO Lines with 40 k
Ω
Pullup Resistors to 3.3 V
DIO <15..14> on the MXP and the two lines on the I
2
C port all have 2.2 k
Ω
pullup resistors to
3.3 V, as shown in Figure 17.
Figure 17.
DIO Lines with 2.2 k
Ω
Pullup Resistors to 3.3 V
<SCLK, MOSI, MISO> on the SPI port and the lines on the PWM and Relay ports all have
40 k
Ω
pulldown resistors to ground, as shown in Figure 18.
Figure 18.
DIO Lines with 40 k
Ω
Pulldown Resistors to Ground
DAC
DAC
0–5 V
AO0
AO1
Exp
a
n
s
ion port
40 k
Ω
FPGA
B
us
S
witch
DIO/C
S
+
3
.
3
V
2.2 k
Ω
FPGA
B
us
S
witch
DIO/
S
CL/
S
DA
+
3
.
3
V
40 k
Ω
FPGA
B
us
S
witch
DIO or Other Line
