When a DIO line is floating, it floats in the direction of the pull resistor. A DIO line may be
floating in any of the following conditions:
•
When the NI roboRIO device is starting up.
•
When the line is configured as an input.
•
When the NI roboRIO device is powering down.
You can add a stronger resistor to a DIO line to cause it to float in the opposite direction.
UART and RS-232 Lines
The NI roboRIO has one UART connected to the UART lines on the MXP and one UART
connected to the RS-232 port.
The UART lines on the MXP are electrically identical to DIO lines 0 to 13 on the MXP. Like
those lines, UART.RX and UART.TX have 40 kΩ pullup resistors to 3.3 V.
The RS-232 lines are compliant with TIA/EIA-232-F voltage levels.
SPI Lines
The SPI port can support up to four devices by using each of the four Chip Select (CS) lines.
I
2
C Lines
The I
2
C lines can be used to connect to a network of I
2
C slave devices.
USB Device Port
You can deploy and debug code by connecting a USB cable from the USB device port on the
NI roboRIO to a computer.
USB Host Port
The NI roboRIO USB host port supports the following devices:
•
Web cameras that conform to the USB Video Device Class (UVC) protocol.
•
Machine vision cameras that conform to the USB3 Vision standard and are backward
compatible with the USB 2.0 specification.
•
Basler ace USB3 cameras.
•
USB Flash drives.
•
USB-to-IDE adapters formatted with FAT16 and FAT32 file systems.
LabVIEW usually maps USB devices to the
/U
,
/V
,
/W
, or
/X
drive, starting with the
/U
drive
if it is available.
Accelerometer
The NI roboRIO contains a three-axis accelerometer, MMA8452Q. Refer to the
Accelerometer
section of the
NI roboRIO Specifications
for the accelerometer sample rates.
16
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ni.com
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NI roboRIO User Manual
