Gyro/Accelerometer Calibration - Kauai Labs navX-MXP User Manual

Robotics navigation sensor

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Table Of Contents

Table of Contents

Guidance

Selecting an Interface

two different formats: Processed Data and Raw data. Streaming is used over the TTL UART

and USB interfaces. More details on the communication detail are available in the

Protocol

Definition.

host can request any data required. Register-based communication is used over the I2C and

SPI interfaces. More details on the communication detail are available in the

Definition.

Comparing the navX-MXP Communication Interfaces

Interface

Speed

Type

SPI

2 mbps

I2C

400 kbps

USB

12 mbps

Recommendations

Based upon the above, the following recommendations are provided for selecting the best navX-

MXP communications interface:

– If mounting the navX-MXP directly on the RoboRIO, the SPI interface is preferred for it's high

speed and low latency.

– If mounting the navX-MXP separately from the RoboRIO using an extension cable and if MXP

IO support is desired, run SPI at a lower speed. The I2C interface is also a reasonable option.

– If mounting the navX-MXP separately from the RoboRIO, and MXP IO support is not desired

and only Processed or Raw Data (not both) is needed, USB may be used. This configuration is

useful when using the navX-MXP magnetometer data, since it makes it possible to mount the

navX-MXP far away from motors. This configuration is also useful when accessing navX-MXP

data from a separate processor, such as a PC or a separate video processor. However, please

note that in certain cases when other USB devices (e..g, cameras) are connected to the same

RoboRIO USB bus, and are used simultaneously with navX-MXP, sometimes the

communication is interrupted. For this reason, USB is not recommended on the RoboRIO,

especially if you are connecting with other USB devices on the same USB bus.