Yes, correct. A new firmware that allows a smoothieboard (or clone) to be used with LinuxCNC!
BLTouch is wired to the control board (PRU) and the IO and PWM (servo position) commands are sent over the SPI interface. Custom M Codes in LinuxCNC as well.
For closed loop control there is an Encoder module which gives position feedback to LinuxCNC.
Unfortunately the SPI cable needs to be as short as possible to ensure reliable communication. Current HAL real-time component runs the SPI at 6.25MHz. A slower frequency could be used but then you would need to run the LinuxCNC servo thread at a slower rate.
This has been an interesting evolution of the last couple of years during development. It started as Arduino based (RADDS based) but then migrated to PlatformIO on Atom using the MBED framework,
I'm now using Visual Studio Code but with the MBED command line compiler. Using MBED OS2 since we don't need a multi threading operating system and the code overhead associated.
Only running on a LPC1768/69 at the moment. It the only hardware I have for development.
For the TMC2209 a module to configure the driver on start-up would need to be written. I have done this for the MCP4451 digipot on the Makerbase MKS SBASE which uses these I2C digipots for current control setting.
Thx Scott.
I have several controllers for my 3d printers.. Mega, Due, Re-arm, mks-base (a 1768 but needed in a delta) and mks-pro + TMC2209. All in vsc with marlin. In the moment i'm on the pro's with the facinating tmc's. I love their way of controlling the steppers. Nearly silent.
I was wondering if there would be a way to use those drivers for chepo small cnc's.
Good job.
Mike
