I’d like to show you all the draft of the 8Axis stepper control board that I have designed. It started with me designing a Step Stick format simpleFOC stepper driver for use with my existing 3d printer boards (Manta 8, Octopus, SKR3 etc.) However, I concluded that all the boards have some design limitations that I felt needed fixing. While the primary intended use for this board is a pick and place machine that I am building, this board design is versatile enough for even the most demanding 3D printing or CNC application.
Main requirements for the board were as follows
- Must be able to use the SimpleFOC step stick driver I created
- Must be compatible with various firmware/software i.e Klipper, Marlin, Reprap etc.
- Must be able to take advantage of the multi core nature of having a microcontroller on each of the step stick and a main controller + Host controller. So if you consider a fully populated board, you would have 8 STM32G4’s, 1 RP2350 (2 Core) + 1 Raspberry PI5. Thats a whopping 14 cores…Fancy that.
- Must be able to be switched between using the Rp2350 or the Raspberry PI as the master
- Have some options for expansion
- Must have Real-time capabilities
So I present you Max14.
I came up with some mode definitions
Mode 0 : Legacy Driver - In this mode, the RP2350 acts as the main controller and can drive the regular non SimpleFOC step sticks using Step/DIR
Mode 1: Legacy Plus - In this mode, the RP2350 acts as the main controller and can drive regular and SimpleFOC step sticks using either Step/DIR or SPI commands (Raspberry Pi is not connected)
Mode2: Host Mode - In this mode, the RP2350 is bypassed and the steppers are fully controlled by the Raspberry PI using SPI
Mode 3: Full Feature Klipper Mode - In this the RP2350 controls the Steppers using SPI. The Raspberry PI controls the RP2350 using UART
Mode4: Full Feature LinuxCNC Mode - In this mode RP2350 controls the Steppers using SPI. The Raspberry PI, running RT Preempt Linux controls the RP2350 like a PRU (Programmable Realtime Unit)
Looking for some early reactions.
