This configuration drives a standard 4-axis 3D printer using the PRU for high speed step/dir pulse generation and a CRAMPS driver board. Current X and Y settings are appropriate for a typical "MendelMax" style printer, with the following settings: max vel = 200 mm/s max accel = 3000 mm/s/s scale = 80 steps/mm Adjust as required for your machine. Make scale negative to invert any axis that is moving 'backwards'.