How to connect to a Fly-Gemini-V2 via SBC

Overview

The Fly-Gemini-V2 STM32F405VGT6 based board with an Allwinner H5 built in for SBC functionality.
Two SD cards are required when using this board. One for the STM32 side and one for the SBC side.

Board Setup

Fly-Gemini-V2 Overview

Jumper Setup

There are two rows of DIP switches that require setting correctly for RRF operation.

Row 1

Row 1 is the row of DIP switches nearest the USB ports.
If you want to be able to access the STM32 chip from the “Board USB” port, then ensure that switches 1 to 6 are in the off position and 7 to 8 are in the on position.

Fly-Gemini-V2 DIP Switches

If you want to be able to acces the STM32 chip from picocom (installed by default) ran from the SBC, then ensure that switches 1 and 2 are in the off position, 3 and 4 in the on position and 5 to 8 are in the off poition.

Row 2

On the row near the EXP headers, ensure that switches 1 to 4 are in the on position.

Fly-Gemini-V2 DIP Switches

STM32 Setup

Firmware File

Choose the correct corresponding firmware (firmware-stm32f4-sbc.bin) from here. Remember to rename it to firmware.bin. Put it in the root of a small FAT32 formatted SD card. This will be placed in the STM32 side of the board. The maximum size supported card is 32GB.

Board.txt

The SD card on the Fly-Gemini-V2 also needs a board.txt file with the following contents.

//Config for Fly-Gemini-V2
board = fly_geminiv2.0
sbc.TfrReadyPin = C.9

Smart Drivers

If using TMC5160 or TMC22XX drivers (where 22XX is either the TMC2208, TMC2209, TMC2225 or TMC2226), the following line must also be added to the board.txt file

stepper.numSmartDrivers = X

Where X is the number of drivers fitted in total.

TMC22XX UART Drivers

The drivers must be continuous and start at unit 0 (unless TMC5160 are also used, which case they must be installed after them). So, for the SKR board, if you have say 3 TMC2208s and 1 other driver, the 2208s must be in slots 0, 1, 2 and the remaining driver in slot 3 or 4. You can use RRF to assign any of those slots to an axis/extruder.

TMC5160 SPI Drivers

If using TMC5160 drivers, the following lines must also be added to the board.txt file.

stepper.num5160Drivers = X
stepper.spiChannel = 0

Where X is the number of TMC5160 drivers fitted. The drivers must be continuous and start at unit 0. So, if you have say 3 TMC5160s and 1 TMC22XX and 1 other driver, the 5160s must be in slots 0, 1, and 2, the TMC22XX in slot 3 and the remaining driver in 4. You can use RRF to assign any of those slots to an axis/extruder.

Sensorless Homing

Supported by only the TMC2209, TMC2226 and TMC5160 If using sensorless homing/stall detection with TMC2209 or TMC2226 the following line must be added to the board.txt file. It is not needed with TMC5160.

stepper.TmcDiagPins = {A.3, B.1, B.10}

Please only include the diag pin numbers where you intend to use sensorless homing on that axis.
For example, if you only intend to use sensorless homing/stall detection on driver 0 and driver 1, only include A.6 and B.1 in your board.txt file.
For more information about setting up sensorless homing, please read this.

Board.txt Location

Place the board.txt file in a directory called “sys” on the SD card and install the SD card in the Fly-Gemini-V2.

SBC Preparation

Download the latest prepared image from here.
The image has DSF installed and ready to go, with the correct transfer pin configured.

Flash the SD Card

Using balenaEtcher, flash the downloaded image to an SD card 8Gb or larger.

Place the SD Card into the Core-SD slot.

Power Up the Board

The board and bed power supply should be 12/24v.
The drivers power supply should be 12/24/48v. 48v should only be used with compatible 48v 5160 drivers.

Turn it all on and you should be good to go.

If using Ethernet, you can either navigate to fly-gemini.local or find the IP address of the rasberry pi using your router. If you don’t have access to that, use something like Fing to scan your network.

SSH into the board

Either via CORE UART USB connection or by using SSH via the network connection. The default username is root and the default password is 1234. Follow the onscreen instructions and change the root password and setup a new user. I recommend using ZSH rather than bash.

How to connect to wireless

If your SBC has onboard wireless capability or if you use a 3rd party wireless adapter on USB supported by Armbian, you can use nmtui-connect to browse and connect to your WiFi AP.

Finally…

Once you’ve connected to the raspberry pi through your router, start to customise your config.g file etc or upload the outputted zip file from the Configurator to the pi using the system tab of Duet Web Control (DWC).

Remember to PID tune the bed and tool

You will need to PID tune your tools and your bed. Please be aware that bed tuning may take up to an hour and tool tuning normally takes around 15 minutes. If it takes longer, that is also fine as up to 30 cycles may be ran.

To tune the bed, run the following command, changing the temperature (the S value) if a different tuning temperature is required.

M303 H0 S60

To tune each tool, run the following command, changing the temperature (the S value) if a different tuning temperature is required. This proceedure will activate the part cooling fans during the final phase of the tuning process so their effect is taken into account. If your printer has more than one tool, make sure each one of them is tuned.

M303 T0 S220

Once the tuning is complete, either copy the M307 command into the heater definitions or send M500, ensuring you have M501 at the end of your config.g.
If the tuning fails at the end, carry on saving the values as in most cases the outputted values still work correctly.
If the values still result in a heater fault, please refer to this wiki page for information about how to adjust the values manually.

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