I have no idea how you could possibly have successfully done anything with Rx to Rx and TX to TX, that makes no sense.
Perhaps if you provide more information, such as which Arduino you have, more information about how you are connecting it and what exactly you are doing then maybe it might make sense.
I have an Arduino Mega 2560, but had the same issue with an Arduino Nano.
I have the Arduino Mega connected to USB on my Laptop.
Here is the part that is confusing.
When I use the Nextion editor
I had originally connected TX to RX and RX to TX and I could not seem to upload data to the Nextion display. By chance after tinkering around a bit, I finally uploaded to the Nextion. Originally I just wrote it off as a bad connections.
I then uploaded a sketch to the Arduino Mega, that involved communication between the Arduino Mega and the Nextion. That communication was not happening.
At that point I realized that I had RX to RX and TX to TX, so instinctely I switched them and the now they were communicating between each other.
It dawned on me that the reason I was able to initially finally upload data to the Nextion was because I had RX and RX & TX to TX.
So sure enough, to successfully upload data to the Nextion, I have to have RX to RX and TX to TX, but then to have communication between the two devices I need to go back to standard RX to TX & TX to RX.
One other strange occurrence that I have notice, is that in order to upload a sketch to the Arduino, I have to remove the jumper that brings power (5v) to the Nextion from the Arduino Mega
I have never tried uploading to the Nextion directly from a PC, I always use the SD card method.
On an Mega (and many other Arduino boards) serial port 0, which is the one you have connected to, is used for the serial monitor, so really you should use one of the other serial ports for your Nextion display.
It's like this:
PC - USB - Mega FTDI (converts USB to serial) Tx - Rx on the actual ATMega2560
.........................................................................................Rx - Tx on the actual ATMega2560
On the board the pin marked Rx is the Rx of the ATMega2560, but is the Tx of the FTDI chip
On the board the pin marked Tx is the Tx of the ATMega2560, but is the Rx of the FTDI chip
So, if you use the USB connection to upload to the Nextion the pin marked Tx is actually the Rx of the FTDI chip, similarly with the Tx pin.
One other strange occurrence that I have notice, is that in order to upload a sketch to the Arduino, I have to remove the jumper that brings power (5v) to the Nextion from the Arduino Mega
The connection to the Nextion display is interfering with the upload connection to the ATMega 2560, ideally you should disconnect it completely. Really you should not be using serial port 0 for your Nextion at all, doing so means you can't send stuff from the Nextion to your Mega and on to the serial port.
Thanks so much,
I am sure it is obvious I am a novice, I try to look around before I ask questions, but there is so much information out there it gets overwhelming.
So if I understand correctly, in my configuration of uploading to the board through my Arduino Mega, it would be best to just keep RX to RX and TX to TX but then use another SET of TX RX pins for the Arduino Mega and the Nextion to communicate with each other.
I using EasyNextionLibrary, Would this be as simple as changing the Serial to Serial1 in any arduino sketch and then connecting to 18 and 19 (TX1 and RX1) on the Arduino Mega?
Arduino was created to help people new to electronics and micro-controllers to learn about them, nothing bad about being a novice, that's kind of the point!
So if I understand correctly, in my configuration of uploading to the board through my Arduino Mega, it would be best to just keep RX to RX and TX to TX but then use another SET of TX RX pins for the Arduino Mega and the Nextion to communicate with each other.
That should work. My preference is to use a micro-SD card for the Nextion configuration, but you don't have to do it that way.
I using EasyNextionLibrary, Would this be as simple as changing the Serial to Serial1 in any Arduino sketch and then connecting to 18 and 19 (TX1 and RX1) on the Arduino Mega?
If you mean Seithan's library I've read a lot of good comments about it, although I've not tried it. I've read a lot of bad comments about the Nextion official library!
Yes, connect it like that, Tx - Rx, change all references for code to the Nextion to Serial1, but be careful NOT to change any that are for the serial monitor. I find it very difficult to spot that particular mistake, even when I'm looking right at it.