The ATmega328 Microcontroller has 1 SerialUART port, called “serial” in code, on legs 0,1.
The ATmega2560 Microcontroller has 4 SerialUART ports, called “serial” and “serial1”-“serial3” in code, on legs 0,1 and 14-19.
In most Arduino boards that these 2 Microcontrollers are used, there is a USB<->SerialUART chip (e.g. the FTDI FT232RL chip), which is already connected to the first SerialUART port.
But consider a case where you take the ATmega328 and ATmega2560 Microcontrollers,
and put them on a PCB, without a USB<->SerialUART chip.
My question is this:
What is the maximum speed that the ATmega328 and ATmega2560 Microcontrollers’ SerialUART port can get to?
I emphasized the fact that there’s no USB<->SerialUART chip, because this chip is usually a bottleneck compared to the speed that the ATmega chips can give.
So consider the case that you want an ATmega328 or ATmega2560 to communicate with some other module, via SerialUART.
Is there a difference in the maximum speed of the Hardware SerialUART of the ATmega328 and ATmega2560?
Thank you for your help