#include "mbed.h"

I2C i2c(p28, p27);        // sda, scl


int addr = 0x46;// 0x46; // define the I2C Address
DigitalOut mcp_reset(p19);
DigitalOut myled(LED1);
DigitalOut blink(LED2);

blink = 1;
myled = 0;
mcp_reset = 1;

int main() {
    char cmd[2];
    //mcp_reset = 1;
    while(1) {
        cmd[0] = 0x0A;            // pointer to command register
        cmd[1] = 0xFF;           // Start ranging, results in cm
        
      
       i2c.write(addr, cmd, 2); // Send command string
       
        wait(0.07);              // Could also poll, 65ms is typical
    }
}

Hello, and sorry for my childish English. I get some errors by simplest things. <<code>> #include "mbed.h" I2C i2c(p28, p27); // sda, scl int addr = 0x46;// 0x46; // define the I2C Address DigitalOut mcp_reset(p19); DigitalOut myled(LED1); DigitalOut blink(LED2); blink = 1; myled = 0; mcp_reset = 1; int main() { char cmd[2]; //mcp_reset = 1; while(1) { cmd[0] = 0x0A; // pointer to command register cmd[1] = 0xFF; // Start ranging, results in cm i2c.write(addr, cmd, 2); // Send command string wait(0.07); // Could also poll, 65ms is typical } } <</code>> The Compiler says myled, blink and mcp_reset has already been defined and has no storage class or specifier. Whats the problem or am i only stupid?

Assign values within main(). Compiler assumes you are defining variables. <<code>> #include "mbed.h" I2C i2c(p28, p27); // sda, scl int addr = 0x46;// 0x46; // define the I2C Address DigitalOut mcp_reset(p19); DigitalOut myled(LED1); DigitalOut blink(LED2); int main() { blink = 1; myled = 0; mcp_reset = 1; ....code }