I have tested a very first arduino project using an Arduino UNO wifi rev2, implementing a simple wifi based NTP client, and it's running ok.
Then I have bought a low cost Arduino clone, an atmega328P-uno-wifi-r3 (Atmel with an onboard ESP8266) and such a newbie I expected to run the same code on this board.
I first had to change library <WiFiNINA.h> to "WiFi.h" in order to compile.
After upload the code to the arduino it fails running because the wifi module is not responding (WiFi.status() returns WL_NO_MODULE).
As I understand codes for "Arduino UNO wifi rev2" or "Arduino with an ESP8266" are not compatible, right ?
The "Arduino UNO WiFi rev2" uses a different processor and a different WiFi module than an Arduino UNO plus an ESP8266. For any WiFi use, they will be incompatible.
Your topic has been moved to a more suitable location on the forum. Installation and Troubleshooting is not for problems with (nor for advice on) your project.
So here is my understanding: the "Arduino UNO + ESP8266" board needs to write and upload 2 distinct programs separately, one writen for the Arduino and the other for the ESP8266. Both programs can be designed to communicate with each other (Serial.write on one side and Serial.read on the other), which could be highly necessary because there is no other way to share variable contents between the 2 programs.
On the other hand the "Arduino UNO WiFi" needs only one program and upload, their both PICs are strongly integrated, you see only one. SO the code design is totally different.
The development with "Arduino UNO WiFi" seems to me quiet comfortable because you have only one self sufficient program. On the other hand the code with board "Arduino UNO + ESP8266" could be more structured since you don't mix internet stuffs and I/O controls.
At this time the "Arduino UNO + ESP8266" price is half than Arduino UNO wifi R3.
"Arduino UNO + ESP8266" can be easily recognizable because the board comes with a DIP switch needed to make settings depending on what you currently want to do (ex. upload to the ESP or to the ATMega), and select the controller you want to access via USB.
