[SOLVED] Problem with hardware serial communication

Projects Networking, Protocols, and Devices
1

Hello guys!

I have a little problem that I cannot understand.
I use Arduino Micro board, where I would like to utilize the second UART port. In my first attempt I hooked up USB-Serial cnverter to my PC and connected it's ground to board's ground and D-SUB 9 PIN 2 (RX) to TX pin on board.
Then I deployed following code:

void setup(){
  Serial.begin(9600);
  Serial.flush();
  Serial1.begin(9600);
  while (!Serial1) { }
  Serial1.flush();
}

void loop(){
  delay(1000);
    Serial1.write(0x35);
    Serial1.flush();
    Serial.write(0x35);
    Serial.flush();  
}

I hoped it will write 0x35 binary data representing ASCII character 5 through bots serial connections (USB - Serial, and UART - Serial1). However, when I set up an launched serial monitor the one connected to Serial showed expected recieved value 0x35 (ASCII '5'), but the when I hooked up port connected to Serial1 I got 0x65 0x00 ('e' and white character). I tried that for few different bytes to send, and always got "weird" results on Serial1.

I have checked baudrates and other settings; I have also used different USB-Serial interfaces.

Could you help me to spot where the problem lays?

2

I use Arduino Micro board, where I would like to utilize the second UART port

What second UART? As far as I know there is only one Uart port!

Serial.flush();

Does this is really doing want you think it will do?

3

Indded,
there is one UART port (addressed by Serial1. routines), and serial over USB (Addressed by Seria. routines).
I have problems with sending data in following setup:

MacMachine(tty.usbmodem)->--over USB-->-Arduino Micro --->---over UART--->---UART2USB converter--->---MacMachine(tty.usbsetial)

4

Solved

I have connected UART TX to RS232 RX. There was missing an inverter between those two.