How to use Serial object at Marlin 2.0.x (SKR v1.3)? (no replies)

Hi,

after several days trying it and reading a lot i need some help...

I'm upgrading a Anycubic Chiron from Trigorilla (8 bits) to SKR v1.3+TMC2208 (32 bits) and I want to use stock display from Anycubic. This display uses a custom protocol via serial communication and everything about it it's at Anycubic repo at GitHub.

I'd like to reuse code from other people (dkoch83) but i'm not able to make it works because everytime Serial object (class HardwareSerial) is used, USB communications is lost. I'm trying to connect stock display with TFT port and in a very simple way, read data from Serial and write it back to same port. To know what's happening i'm using a protocol analyzer so i can see data from display and if there's some answer.

My last attempt was the most simple test but only enable SERIAL_PORT to -1.

- Open Serial at setup() with Serial.begin(115200);
- Read data from Serial and write it back at loop()

if (Serial.available()){
      byte b = Serial.read();
      Serial.print(b);
    }

This test doesn't work and USB communication down.

If I enable SERIAL_PORT -1 and SERIAL_PORT_2 0, host communications works fine in both ports USB and TFT but i don't want TFT port as standard host.

I know some people did something like i'm trying with custom serial communication but there's must be something i can't see... :(

My project at GitHub: [github.com]

Help will be appreciated :)