MKS TFT32/28 alternative firmware.

Early alpha, most of functions seem to be working. Printing from USB stick and on-screen SD card is not complete.

Since Duet has no protection from over-voltage and MKS TFT has 5v UART do not connect MKS TFT directly to the Duet board. Use level shifter (Duet 3.3v <-> MKS TFT 5v): Adafruit level shifters

ST-LINK    MKS-TFT32: 
5v         AUX-1 5v 
GND        AUX-1 GND 
SWDIO      JTAG pin 4 
SWCLK      JTAG pin 5 

3.3v   GND   GND 
SWDIO  SWCLK RESET

Disconnect MKS TFT from printer before connecting ST-LINK. Do not connect ST-LINK 3.3v pin.