I have an HMI, Arduino Uno, stm32, and blue pill, the default interface of my HMI is RS232, I need to solder it to TTL interface when I use Arduino Uno, and when I use stm32 I need to convert it to RS232 or change the level by code.
So do I need to pay attention to this when I use the blue pill?
This is a schematic of the connection to the Arduino.
