从Arduino串行读取似乎非常不稳定

Question

I have the following simple code to read commands sent from the computer to an Arduino Mega board:

void get_command() 
{
    char received;
    int index = 0;

    while (Serial.available() > 0) {

        if (index < BUFFER_SIZE -1) {
            received = Serial.read();

            if (received == '\n') {
                buffer[index] = '\0';
                parse_command(buffer);
            } else {
                buffer[index++] = received;
            }
        } else {
            Serial.println('666'); // buffer overflow
        }
    }
}

The commands are like A123 B123 C123 D123\\n

Basically a sequence of space separated instructions, were each instruction starts by a letter and follows by a number. A command ends with a "\\n".

Reading this seems to be very unstable. Sometimes I get the command perfectly, sometimes I miss the first letter, sometimes a pair of them, sometimes it starts by the number,...

I am sending the commands through the serial monitor, set to newline.

Before having this code, I'd simply check for the size using Serial.available, then Id wait a second to fill the buffer, and then I'd copy the buffer to a char*. This worked flawlessly. I am doing now this loop waiting for a \\n, which seems more elegant, but it is being very unstable.

Answer 1

Code works by simply adding a delay(100) after the first Serial.available()

This is the code:

void get_command() 
{
    char received;

    if (Serial.available() > 0) {
        delay(100); // let the buffer fill up
        int index = 0;

        while (Serial.available() > 0) {

            if (index < BUFFER_SIZE -1) {
                received = Serial.read();
                if (received != '\n') {
                    buffer[index] = received;
                    index++;
                } else {
                    buffer[index] = '\0';
                    parse_command(buffer);
                }
            } else {
                Serial.println('666'); // buffer overflow
            }
        }
    }
}