If communications work at 9600 Baud but not at 115200 Baud, the problem is clearly an inaccurate rate.
That always happens with internal 8 MHz RC oscillators that are not properly calibrated and with many Arduinos using cheap resonators.
If communications work at 9600 Baud but not at 115200 Baud, the problem is clearly an inaccurate rate.
That always happens with internal 8 MHz RC oscillators that are not properly calibrated and with many Arduinos using cheap resonators.