Firmware Flashing Instructions

Choosing the Firmware Type

Please confirm the connection method first

• When not using a CAN toolboard: select USB firmware.
• When a CAN toolboard is required: select USB Bridge CAN Firmware.
• The Gemini V3 has an onboard CAN transceiver chip, so no external CAN module is needed.
• Only one of the two firmware types can be selected; do not flash both at the same time.

Firmware Type	Applicable Scenario	Advantages	Confirm Before Selecting	Operation
USB Firmware	When not using a CAN toolboard	Stable communication, simple configuration	Use the USB firmware when not using a CAN toolboard	Compile USB Firmware
USB to CAN Bridge Firmware	When a CAN toolboard is required	Can connect multiple CAN devices, reducing USB usage	Only select when a CAN toolboard is required; confirm CAN wiring, terminal resistors, and CAN baud rate settings are consistent	Compile USB to CAN Bridge Firmware

DIP Switch Introduction

• The Gemini V3 uses DIP switches to select the connection method between the lower computer and the onboard upper computer or the external Type-C port. If the DIP switches are not set correctly, the upper computer will not be able to connect to the lower computer. Please pay close attention to this!!!

Notice

Please note that the DIP switches must be set to the specified positions to properly connect to the upper computer.

Connecting to the Onboard Upper Computer

• Turn DIP switches 1 and 2 ON to connect the lower computer to the onboard upper computer via the built-in USB.

• Turn DIP switches 3 and 4 OFF; otherwise, the connection between the lower computer and the upper computer will be affected.

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• After setting the DIP switches this way, the lower Type-C port will be occupied by the lower computer. Do not connect other devices to it.

Connecting to an External Upper Computer

• Turn DIP switches 3 and 4 ON to connect the lower computer's USB to the onboard Type-C port.

• Turn DIP switches 1 and 2 OFF; otherwise, the connection between the lower computer and the external upper computer will be affected.

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5-Pin DIP Switch Description

Tip

• The 5-pin DIP switch is used for RRF SBC mode.
• No changes to the 5-pin DIP switch are required when using Klipper.