Arduino for STM32

Hello!
I have a next code in in my Arduino nano:

#include <SoftwareSerial.h>

SoftwareSerial mySerial(2, 3);
void setup()
{
// Open serial communications and wait for port to open:
Serial.begin(115200);
// set the data rate for the SoftwareSerial port
mySerial.begin(9600);
}
void loop() // run ...

Hello!
I use a while an Arduino, but now i am still add STM32 also.
Use Linux and for compiling i use the mbed online tool.