This firmware is customized for using skr 1.4 turbo with Anycubic 4max pro's TFT DWIN Display. I am not author of the code, the code is taken from here: https://github.com/Poket-Jony/Marlin-A4MaxPro-2.0.x
32bit board with LPC1768, support marlin2.0 and smoothieware, support lcd2004/12864, On-board TMC2130 SPI interface and TMC2208 UART interface no additional wiring is
BIGTREETECH SKR V1.3 YouTube Video:here
This article explains how to configure all different TMC2209 dirvers from different procuders in SKR V1.4 & V1.4 Turbo