UART features of the FluidNC fork

Hi @bar and Roman,

Is there some resources you could point the community to regarding the UART (JST connector) features and potential usage of the Maslow’s FluidNC fork? Or maybe some docs where the community could start created a “Serial Port User’s Guide”. I did find the following so far:

With my decades of experience (and being a terminal user), that sole serial port is a very important interface.

I’m very aware of the esp32’s storage limitations. Being new to the Maslow community (I’ve to still assemble mine), I don’t have the practical experience you and existing community does. I’m curious as to how the community can maximize the serial port OR its currently available features:

  • general interface / menu - AT, G-Code, simple menu, etc.
  • file transfers (using xmodem) in case WiFi is down – like uploading a config, instructions, or other files.
  • status feedback, etc.
  • firmware rescue

New train of thought. Crazy idea time:

The UART JST might be something the community could leverage with the AUX pin’s JST to make a potential “daughter card”.

I recently came across a UART to WiFi module based on the NL6621M chip. Pre-made modules run $3 - $5 US. When I found this, an idea crossed my mind that it would be much safer to troubleshoot the spindle control wireless vs tethered.

For those interested in this rabbit hole, here’s some links I found on the chip. A lot of findings is chinese-only.

Thanks for your feedback. Cheers.


One thing that might be useful. I notice that fluidnc exposes a “telnet” in its configuration, which I believe serial messages go to. I will give it a try and see if this will work for this purpose.

Edit: It does… telnet <maslow_ip> 23 and you are talking to it :slight_smile:


Writing up full documentation for everything is very much on my TODO list, but it’s behind getting hardware shipped out to everyone who is waiting and getting everyone up and calibrated so it might take a little while. In the meantime I’m super happy to answer any specific questions.

Maslow4 actually has two serial connections. The main one (if you wanted to control the machine by serial) is a serial over USB C connection using the USB C port and the ESP32s built in USB support. That should be fully working as it is with USB based controllers like UGS.

The second serial connection on the AUX port could also receive gcode, but it’s really more there for future expansions like adding a screen or a printer head or something.