Garbled Serial output is fixed with mis configured baud. why?

Using Arduino Programming Questions
1

Hello,
i got my hands on the pro mini with FTDI breakout. Among first things i tried was :

void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
delay(10000);
  Serial.println("test"); 
}

which, to my surprise was producing a garbled text on the monitor. ( I tried in PlatformIO and Arduino 1.6.5 - neither worked).

The Baud in monitors was set to 9600.

To my surprise the BAUD in the monitor that worked was 19600. See attached.

My question is why ?

I have nothing connected to Mini. it sits on the wooden desk with ftdi and usb cable - so not a grounding issue.
Appreciate.

Screenshot from 2016-10-07 01-11-32.png
Screenshot from 2016-10-07 01-11-32.png783×707 31.7 KB

2

AZZ:
Hello,
i got my hands on the pro mini with FTDI breakout. Among first things i tried was :

void setup() {

// put your setup code here, to run once:
Serial.begin(9600);
}

void loop() {
 // put your main code here, to run repeatedly:
delay(10000);
 Serial.println("test");
}




which, to my surprise was producing a garbled text on the monitor. ( I tried in PlatformIO and Arduino 1.6.5 - neither worked).

The Baud in monitors was set to 9600.

To my surprise the BAUD in the monitor that worked was 19600. See attached.

My question is why ?

I have nothing connected to Mini. it sits on the wooden desk with ftdi and usb cable - so not a grounding issue.
Appreciate.

Your Pro Mini will be either an 8MHz or 16MHz version - you didn't say which - (one is twice as fast as the other).
Your baud rates 9600 / 19200 are out by a factor of 2.
Does that help you isolate the problem ?

3

6v6gt:
Your Pro Mini will be either an 8MHz or 16MHz version - you didn't say which - (one is twice as fast as the other).
Your baud rates 9600 / 19200 are out by a factor of 2.
Does that help you isolate the problem ?

My bad. It is 3.3V 328, so it is (should be) 8Mhz.

4

after looking at my purchase transaction, i'm not so sure ( that it is 3.3v/328P) anymore.
It maybe a 5V version, which will give me 16Mhz.

Assuming it is 16Mhz, why i'd observe such an behavior than?

5

Assuming it is 16Mhz, why i'd observe such an behavior than?

Wrong board setting in the IDE?