Thank you so much VideoLiam for reviewing the code I did make changes in my CompButton.cpp code and added Serial.Begin(); I also reviewed the Voltage level shift comment thatScruffR made here Although the comments are made with Particle Electron in mind, It may also apply to Particle Photon. To check I did connect
the common ground for both Nextion and Photon and only one Pin from Nextion goes to USBTTL all the other pins Now go to Photon
The Problem was identified when the up and down arrow did not scroll through the list Here is the video link
So As part of Troubleshooting, Where the problem is communication between Photon TX and RX with Nextion is. I use the CompButton code from Nextion Library the library does not require Serial.Begin() However looking at Particle documentation I understand if you are using photon to communicate to Nextion Serial.Begin(); required in the code. If one uses Nextion by Itself, the Button does work here is thelink to the video that is able to increment the Number
To answer ScruffR question Yest I have Flash Photon 0.7.0 using Particle CLI command Particle Update from Dos Command Prompt. I also modified the CompButton.cpp and saved it as SerialBegin.cpp after adding Serial.Begin(); before the printing to Serial
I then Flash the photon using particle flash --usb SerialBegin.bin that was compiled using SerialBegin.cpp
However the number will not increase in value so the communication between Photon and Nextion via RX and TX is still a mystery to me.
One other problem I notice is Power will NOT stay powered ON when I use USBTTL to power both Photon and Nextion, Perhaps resistor are needed in the circuit to make sure there is enough amps for photon to stay powered on when powered through Vin and GND pin of Photon right above TX pin