on the regular UNO Rev 3 i'm using 115200 to serial communicate between PC and UNO.
with the UNO Wifi Rev 2 this seems not possible, the data gets mangled.
with a the speed of 57600 this doesn't happen.
is this according to specifications?
rolf
Gee, it ought to work faster than that...
I was able to get 115200 out of the mega-tiny parts which use the same uart peripheral, at both 16 and 20mhz base frequency.
The ATmega32u4 mEDBG chip doesn't do a very accurate 115.2kbps.
Try using "Serial.begin(111111);" in your sketch (and leaving the serial monitor set to 115200)
(it "should" work OK with the ATmega4809; with older ATmegachip, like you'd find on an Atmel Xplained mini Atmega328p board, not only was the 115.2k "off" on the 32u4 (-3.5%), it was off in the opposite direction of the 328p (+2.1%) The ATmega4809 has a fractional BRG divisor, so it should be more accurate. OTOH, it has a less accurate clock...)
There's must be some issue with your code as 115200 works pretty fine with Wifi Shield as well. So share your code to get proper help.
all in all it seems to be another problem than the baudrate itself.
see this post:serial port UNO Wifi Rev 2 not sending or responding
https://forum.arduino.cc/index.php?topic=643836.0
@ jackthom41 sorry but the sketch is working on the regular UNO perfectly.