Baud rate question

Does increasing baud rate have any disadvantages?

vulture2600: Does increasing baud rate have any disadvantages?

Yes, if the device on the other end doesn't match.

Is that the only issue? Is there a limit to how much you can raise both baud rates before it starts to affect the rest of the sketch?

Is there a limit to how much you can raise both baud rates before it starts to affect the rest of the sketch?

It depends on what you are doing at each end, the data might be arriving faster than than the sketch can cope with it.

I guess that was what I was getting at; if cranking up the baud rate eventually hits some kind of limit. Thanks.

Most of the limit is in if the actual signals can make it to the other end intact. As a cable gets longer it has more capacitance and so the rise time of the signal is slower. You get into trouble when the rise time is longer than the baud time.

Also, increasing the baud rate will increase the amount of CPU power used by the CPUs (on both sides.) At 110bps, you're looking at 10 interrupts per second, which is nothing. At 115200bps, you're looking at 11000 interrupts per second, which is somewhat worrisome. At some point, (if the data is essentially continuous). you start starving your non-interrupt code for the CPU time that it needs to do things. A bit beyond that, and your ISR code contains more instructions than will execute before the next byte comes in, and you start losing data. 115200 is pretty close to the practical limit for a 16MHz CPU like the AVR in the Arduino.

Awesome, thanks!