I am in the initial planning stages of a controller for my aquarium, and am currently trying to map out all my pins in Excel before starting to code and wire things up.
I have 4 probes (Atlas Scientific SDS kit) that I would like to use which all connect to a 'stamp' that requires a serial connection to Arduino. I see that the Due has pins RX0-3 and TX0-3, but have read that RX0 and TX0 are used for the USB communication.
All Arduino boards have at least one serial port (also known as a UART or USART): Serial. It communicates on digital pins 0 (RX) and 1 (TX) as well as with the computer via USB. Thus, if you use these functions, you cannot also use pins 0 and 1 for digital input or output.
This leads me to believe that I can use pins 0 and 1 for serial communication with for example a probe.
The Arduino Due has three additional 3.3V TTL serial ports: Serial1 on pins 19 (RX) and 18 (TX); Serial2 on pins 17 (RX) and 16 (TX), Serial3 on pins 15 (RX) and 14 (TX). Pins 0 and 1 are also connected to the corresponding pins of the ATmega16U2 USB-to-TTL Serial chip, which is connected to the USB debug port. Additionally, there is a native USB-serial port on the SAM3X chip, SerialUSB'.
But then this quote muddies it for me, and I can't tell if I can use pins 0 and 1 or if they are reserved.
So my question is, if I am not using the USB port for anything aside from uploading my code (ie once the controller is complete and attached to the aquarium) can I use all 4 serial ports for my probes?
I do also have a Mega that I will likely be using as a slave device for additional pins, but would prefer to have all of the probes handled through 1 board.
Sorry for the thin details, I really don't have much else at this point. Hope my question makes sense.