usbtest.ino

#if defined(ARDUINO_SAMD_ZERO) || defined(ARDUINO_SAM_DUE)
#define SERIAL_PORT SerialUSB
#else
#define SERIAL_PORT Serial
#endif

uint8_t speedTestBuffer[256];

void setup()
{
  digitalWrite(LED_BUILTIN, LOW);
  pinMode(LED_BUILTIN, OUTPUT);
  
  SERIAL_PORT.begin(115200); //921600

  //digitalWrite(LED_BUILTIN, HIGH);
}

void loop()
{
  
  int c = SERIAL_PORT.read();
  delay(10);
  digitalWrite(LED_BUILTIN, HIGH);

  if (c == -1)
    return;

  switch (c)
  {
    case 'b' :
      burstSendTest();
      break;

    case 'l' :
      loopbackTest();
      break;

    case 's' :
      speedTest();
      break;

    case 'k' :
      slowTest();
      break;
  }
}

void burstSendTest()
{
  // Send a burst of 1.000.000 bytes of data
  for (uint16_t i=0; i<20000; i++)
  {
    // 25 bytes
    SERIAL_PORT.print("0123456789abcdeABCDE=)(/&");
    // 25 bytes
    SERIAL_PORT.print("qwertyuiopasdfghjklzQWERT");
  }
}

void loopbackTest()
{
  while (true)
  {
    int c = SERIAL_PORT.read();

    if (c != -1)
      SERIAL_PORT.print((char) c);
  }
}

void slowTest()
{
  while (true)
  {
    SERIAL_PORT.println("0123456789abcdeABCDE=)(/&");
    delay(500);
  }

}
void speedTest()
{
  int frameSize = SERIAL_PORT.parseInt();
  
  if (frameSize < 1)
  {
    digitalWrite(LED_BUILTIN, HIGH);
    while (true);
  }

  uint8_t speedTestBuffer[frameSize];

  for (int i = 0; i < frameSize; ++i) {
    speedTestBuffer[i] = (uint8_t) (i & 0xFF);
  }

  while (true)
  {
    SERIAL_PORT.write(speedTestBuffer, frameSize);
  }
}