Thread: navX Micro I2C voltage and Roborio
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Unread 22-12-2016, 18:52
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Re: navX Micro I2C voltage and Roborio
Quote:
Originally Posted by cpapplefamily View Post
Dose the 5v pin and the NavX Micro still NEED 5v?
The navX-Micro can be powered successfully even with 3.3V on the "5V" pin on the I2C connector, as long as it's really 3.3V.

The processor runs down to 1.7V, and the MPU-9250 runs down to 2.4V.

The navX-Micro has a voltage regulator with a max voltage drop of 725 mV.

So, when 3.3V is applied, the lowest output voltage will be 3.3 - .725 = 2.575.

The remaining headroom in the worst case is 2.575 - 2.4 = 175mV.

As long as you're OK w/that headroom, this configuration works.

NOTE: If you're getting power from the RoboRIO, be aware that if a stage 2 brownout occurs, the RoboRIO will remove power from the 3.3V "user" rail. For this reason, it's highly recommend to connect a USB cable to navX-Micro (if only as a backup power supply). navX-Micro - like navX-MXP - has a dual power supply input, and the RoboRIO USB ports provide 5VDC from a buck/boost regulator that continues generating current even during a stage 2 brownout. Please see the navX-Micro Best Practices for more details.
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