@vic003 Voilà les lignes que j'ai dans mon Marlin qui fonctionne avec une carte mère BTT SKR mini E3V2 écran BTT E3V3
#define SERIAL_PORT 2
/**
* Serial Port Baud Rate
* This is the default communication speed for all serial ports.
* Set the baud rate defaults for additional serial ports below.
*
* 250000 works in most cases, but you might try a lower speed if
* you commonly experience drop-outs during host printing.
* You may try up to 1000000 to speed up SD file transfer.
*
* :[2400, 9600, 19200, 38400, 57600, 115200, 250000, 500000, 1000000]
*/
#define BAUDRATE 115200
//#define BAUD_RATE_GCODE // Enable G-code M575 to set the baud rate
/**
* Select a secondary serial port on the board to use for communication with the host.
* Currently Ethernet (-2) is only supported on Teensy 4.1 boards.
* :[-2, -1, 0, 1, 2, 3, 4, 5, 6, 7]
*/
#define SERIAL_PORT_2 -1
//#define BAUDRATE_2 250000 // :[2400, 9600, 19200, 38400, 57600, 115200, 250000, 500000, 1000000] Enable to override BAUDRATE