I2C/Spi Slide Switch; Led; Backup Power Supply - u-blox EVK-M9DR User Manual

The safe boot button is used to set the unit in safe boot mode. In this mode the receiver executes only
the minimal functionality, such as updating new firmware into the SQI flash. USB communication is
disabled while in safe boot mode.
To set the receiver in safe boot mode:
• Press and hold the BOOT button.
• Press the RST button.
• Release the RST button.
• Release the BOOT button.
To use UART in safe boot mode, a training sequence needs to be sent to the receiver. The training
sequence is a transmission of two bytes (0x55 0x55) at the baud rate of 9600. Wait for at least 100
milliseconds before the interface is ready to accept commands.

2.7 I2C/SPI slide switch

⚠
The switch must be kept at the I2C position to ensure correct operation of the device!
⚠
Contact u-blox technical support for assistance if required.

2.8 LED

On the front panel of the unit, a single blue LED may be configured to follow the receiver time pulse
signal. If there is no GNSS fix, the LED will be lit without flashing.

2.9 Backup power supply

The back side of the unit has a micro-USB connector for providing backup voltage for the receiver. See
the NEO-M9V Integration manual [1] for more information about backup voltage.
⚠
If a power bank is used for backup power, ensure that the power supply is not interrupted due to
low current intake.
UBX-21049360 - R01
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EVK-M9DR - User guide
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