Noè Murr

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5 years, 4 months ago.

UARTSerial does not write bytes

Hi all,

I have the following code:

first code

int main() {
    DigitalOut led(LED1);
    UARTSerial pc(USBTX, USBRX, 921600);

    while (true) {
        char r = 0;
        char w = 10;
        
        led.write(1);
        pc.read(&r, 1);
        led.write(0);

        wait(0.1);

        pc.write(&r, 1);

        pc.sync();
    }

    return 0;
}

The problem is that if I leave the code as it is it writes -1 on serial.

If I change the write call to send the w variable I simply don't read anything from the pc.

second code

int main() {
    DigitalOut led(LED1);
    UARTSerial pc(USBTX, USBRX, 921600);

    while (true) {
        char r = 0;
        char w = 10;
        
        led.write(1);
        pc.read(&r, 1);
        led.write(0);

        wait(0.1);

        pc.write(&w 1); // changed the variable

        pc.sync();
    }

    return 0;
}

What is the problem?

Thank you.

1 Answer

Desmond Chen
5 years, 4 months ago.

Hi Noè,

It seems you miss a comma in your code, your code snippet is pc.write(&w 1);, I believe it should be pc.write(&w, 1);

Let me know if you have any questions.

Thanks,

Desmond