makerbase
MKS has limit display to 18 characters, but you can use it normal.
@dgorbunov If you use the lvgl ui interface, you will use MT_DET_PIN.
For your first question, I think Turn off motor when you moving motor is can not, because firmware this function is need motor enter stop status, so, we need wait...
stm32f402rct6 is the same as stm32f401rct6
Is the serial line reverse?
1. MKS TFT28 use DC12V power by DC terminal 2. Set the motherboard baud rate and connect AUX-1 correctly
Should be caused by RAMPS problems. Need to see how the corresponding pins are distributed
MKS TFT28 AUX-1 pin 
@daniellezama You can refer to MKS SGEN_L Wiki: https://github.com/makerbase-mks/SGEN_L/wiki/Display_MKS_TFT35
Hope others can help you, as I haven't chance to drive a K40.