Serial.begin(250000). Is there any reason not to use the maximum speed?

The first time I used Serial.print() etc I used 9600 baud. I can't remember if it was the default when I first got the Arduino, or if it was just what I'd seen others using in examples.

Anyway, I've noticed that in my serial monitor window it will allow me to select up to 250k baud, and I've tested that my serial print()'s work just fine at that speed (with an appropriate Serial.begin of course).

So is there any down side to using the highest available speed when using the serial monitor. Any reason not to do it?

So is there any down side to using the highest available speed when using the serial monitor. Any reason not to do it?

Probably not, just remember if you post a program to put a comment like "set serial monitor baud rate to match" after Serial.begin(). Else you'll get replies of "Your program fills my serial monitor with garbage" because their's is set to the default 9600.

outsider:
Else you'll get replys of "Your program fills my serial monitor with garbage" because their's is set to the default 9600.

Ok, so does this mean that 9600 is kind of a default or defacto standard then?

In the old days 9600 baud was fast. It is often used but I don't think there is any sense in which it is a standard.

I don't know if it works with the Serial Monitor but 500,000 baud works very well with my Python programs. In the Atmel datasheet there is a table of all the baud rate options and the timing errors associated with them for different Arduino clock rates. At 16MHz and 8MHz 500,000 baud has no error.

I would not be surprised if rates higher than 9600 cause problems with SoftwareSerial.

...R

Plug an Arduino into USB, open the IDE and select a serial port, then click on the serial monitor button and see what baud rate is, I don’t know if it’s 9600 or the last used.

Robin2:
I don't know if it works with the Serial Monitor but 500,000 baud works very well with my Python programs.

Hi Robin. In my serial monitor 250,000 is the fastest speed offered.

I would not be surprised if rates higher than 9600 cause problems with SoftwareSerial.

Yes, with a software emulated UART I certainly wouldn't want to push it. :slight_smile:

outsider:
Plug an Arduino into USB, open the IDE and select a serial port, then click on the serial monitor button and see what baud rate is, I don't know if it's 9600 or the last used.

Hi outsider. For me it's the last used. Since I tested with 250000 it comes up by default with that each time I open serial monitor.

Come to think of it though, I don't remember ever changing any settings in serial monitor when I first started using it. I was just always using 9600 and it always worked. So I believe that 9600 must have been the default when I first downloaded the software.

I honestly think 9600 causes more than often causes problems. I use 115200 as 'default' for my programs, don't know why. I was writing some IR software for a toy with the Arduino, 9600 baud caused too much delay at each Serial.print and there was no buffer on the IR sensor... It took ages to figure it out...

I tested this even over long cables (10m+) with no errors. My father used to work with intercity communications before the internet and they used 9600 because over longer distances (a few kilometers) higher baudrates had difficulties... So I can see why you would use it for that, but over a shielded short USB cable, the sky is the limit I say...

On a "real" serial port , with no usb , Going on higher datarate could be an issue when wire lenght over about 10 feet, or cheap cable, are used.

When directly coupled to usb converter , as most arduino are , there is no issue

J-F

Robin2:
In the old days 9600 baud was fast. It is often used but I don't think there is any sense in which it is a standard.

Back in my day....
We used a mix of DEC VT80 and VT100 terminals and a couple of printer terminals. They were all set to 9600 Baud out of the box.

Please note that this thread is about 3 years old.

I always wonder how people manage to find them.

I always wonder how people manage to find them.

[serial begin maximum speed site:https://forum.arduino.cc](http://serial begin maximum speed site:https://forum.arduino.cc)