FYSETC S6 3D Printer Board for OnStep Telescope Controller

I have been using the FYSETC S6 V1.2 3D printer board as my telescope controller for a few years.

Advantages

This is a feature rich board that has the following advantages:

• Already soldered and ready to go
• Supports all features of OnStep (limit switch, PEC, ...)
• Supports built-in dew heater functionality

Both version 1.2 and 2.0 work well with OnStep.

Youtube Videos Demonstrating FYSETC S6

The following playlist has several videos on the FYSETC S6 board with OnStep.

These include features such as GPS, slewing speedily at 4 degrees/second, integrated dew heater, and more.

Precautions: Before You Power Up!

It is extremely important that you set the 5V jumpers correctly on the version 2.0 board.

This jumper has two settings: USB5V or DC5V.
If you set the jumper to USB5V, and apply 12V-24V power in to the board, you may permanently damage it!

Therefore, use USB5V only for flashing the board, and never apply 12V-24V while the jumper is set to USB5V.

To be always safe, I only set this jumper to DC5V, and always power it using an old laptop power supply at 19V. That way, I never make the mistake above and ruin the board.

BOOT0 jumper

The S6 board uses DFU mode to flash programs to it.

In order to set the board to DFU mode, version 1.2 has a momentary switch to do that.
Version 2.0 of the board is different: it has a BOOT0 jumper.
But instead of a regular jumper, I connected two wires from the jumper to a small switch that is attached to the case's exterior. This allows me to flash the board without opening the case.

The sequence is as follows:

• Power off the board
• Set the switch to "Flash" mode
• Connect the USB cable to the laptop
• power up the board from the 19V source

Once flashing is successful, power off, set the switch to run mode, and power on again.

Arduino IDE Settings for the S6

The supported version for STMicroelectronic Board Manager is 2.2.0.

You have to set the IDE as follows under Tools -> Boards:

STM32 Boards               = 3D printer boards
Board part number          = FYSETC_S6
U(S)ART support            = Enabled (generic 'Serial')
USB support (if available) = CDC (generic 'Serial' supersede U(S)ART)
Optimize                   = Smallest -Os default
C Runtime Library          = Newlib Nano + Float Printf/Scanf
Upload Method              = DFU

Verify That OnStep Is Running

After you complete flashing OnStep to the board, you should power off the board, and remove the BOOT0 jumper.

When you power up again, the board should be in normal mode (not DFU), and running OnStep.

To verify that OnStep is running normally, you need to use the Arduino IDE Serial Monitor. Set the baud to 9600, and enter the command:

:GVM#

You should receive back a message that includes the version number of OnStep, for example:

OnStep 4.24m

You are now ready to use OnStep on the FYSETC S6 ...

No COM port or USB device in lsusb

Some users have reported that they can access OnStep from Arduino's Serial Monitor immediately after flashing, but if they power off, remove the BOOT0 jumper, and power on again, there will be no COM port on Windows (or USB device in lsusb on Linux).

If that is the case, then the bootloader on your board is corrupted.

To solve it, perform the steps below:

• Download the .zip file below
• Unzip the file to extract the .bin file
• Flash the file named s6-v2.0-bootloader.bin to your board at address 0x8000000 using STM32CubeProgrammer (or dfu-util on Linux).
• Flash OnStep normally

This above procedure is verified to work only on the V2.0 version of the board.