I have a home made CNC machine that uses a Rambo board (basically a mega2560p).
From literally forever investigating this, I cannot seem to enable a second serial port, as it seems the Marlin code is not set up properly to support it.
I am trying to make a serial remote control to send basic commands to the CNC (G-code), such as home etc.
Normally, I do this in the printing software, but it would be good to be able to control the CNC immediately without firing up my laptop.
There is an LCD attached to the Rambo, but the interface is horrible.
My question (got there in the end), is could you 'mix' serial inputs?
I am never going to operate two input devices at the same time, so could you connect two serial transmissions to the same RX pin on the Rambo board>
I would imagine you need some kind of resistor in-line.
Obviously, the data will be corrupt if it receives data at the same time, but that won't happen. If it did, then nothing happens anyway.