I have been doing real time programming for many years, more than 40, and now I putting my nose into it again because of the easyness in using stuff like UNO and all available shields instead of wire wrapping everthing myself.
The environment is new to me. Can You sort out the things for me about the communication options available using an UNO?
There is the use of the USB connector and "Serial monitor" and I use it for debugging info. Looking at the UNO board I see "RX/TX" printed at the location of digital in-/out- put D0 resp. D1. It looks obvious that D0/D1 can not be used for digital I/O at the same time as serial communication is used on TX/RX.
Then there is the I2C using SCL and SDA. I find them near the USB connector but I feel I have seen videos using A0 and A1 for them. Can You sort this out for me? Is SCL/SDA hard wired to A0/A1?
Is it possible to communicate to/from an UNO on 3 different channels, USB, TX/RX and I2C?