Hey guys, I’m new here. I downloaded Arduino IDE 2.0.0-rc9 and I tried a simple code “hello world”. I’m using an Arduino UNO. I did verify and upload it, but nothing shows up on Serial Monitor. It’s 9600 baund, it’s com3. Can someone help me? I’m losing my mind.
Thank you 
If you add code to blink the LED on pin 13 of the UNO does it blink when loaded and running ?
Also Google how to take a screenshot for a better image or, better still, use the arduino ide built in option for taking a copy for forum of your code which will put it in code tags
The monitor does not auto-start (as wokwi).
CTRL-SHFT-M to bring up the monitor then ALT-TAB to bring the monitor to the top.
Yes it blinks when I upload the code.
Have you opened the output of the monitor
Its the same, even if I click it on Tools<Serial Monitor or CTRL+ALT+M
Hi @albaniaboy. Please upload this sketch to your Arduino board and then tell us whether you see anything in the Serial Monitor:
void setup() {
Serial.begin(9600);
}
void loop() {
Serial.println("hello");
delay(1000);
}
The code in your latest screenshot only prints once right after the code starts running. Even though we would still expect to see it in Serial Monitor (and consider it a bug if we didn't), the code I shared is a bit more basic of a "smoke test" because it does not rely on the Serial Monitor receiving data at that specific instant in time.
In your last post, you can see two ?? square things ??... that tells me that the BAUD RATE on your Serial Monitor is not the same as your Serial.begin(9600) statement. Both should be the same. Look in the lower-right portion of your serial monitor (it is off the screen right now) for a button to click and change to 9600.
albaniaboy is using Arduino IDE 2.x. The Arduino IDE 2.x Serial Monitor currently has a different layout from the Arduino IDE 1.x Serial Monitor you are describing.
The baud rate menu is at the top right corner on the current Arduino IDE 2.x Serial Monitor:
(thank you. sorry for not paying attention to the image and assuming 1.x IDE)
No worries. It is a bit confusing to have two different user interfaces to support depending on which version of the Arduino IDE is in use. In general, the design of 2.x follows 1.x closely, but Serial Monitor does not.
The plan is to rework the Arduino IDE 2.x Serial Monitor in the near future. The new design will use a dedicated window, which lends itself better to the Arduino IDE 1.x layout than the current panel-based approach. Probably the finished Serial Monitor will have a similar design to the Arduino IDE 2.x Serial Plotter.
First of all thank you for your respond but it didnt work. I got 3 squares this time. When I opened Arduino, it showed me the new update option but I chose "not now". Maybe I should get the update?
Does the problem also occur if you try it with Arduino IDE 1.8.19?
The download links for it are here:
Ah, very interesting. There was a change in the default setting for this upload verification between Arduino IDE 1.x and 2.x. It is possible that the sketch program is being corrupted in some way, and that corruption is the cause of the program not working as expected. The corruption would not be detected when using the default setting in Arduino IDE 2.x
Please try this:
- Start Arduino IDE 2.x
- Select File > Preferences... from the Arduino IDE menus.
- Check the box next to "☐ Verify code after upload".
- Click the OK button.
- Select Sketch > Upload from the Arduino IDE menus.
- Wait for upload to finish.
Do you get a similar "avrdude: verification error; content mismatch" error in Arduino IDE 2.x?
In IDE 2.0-RC9.1 output sent to the Serial Monitor does not show up until you click in the window, which seems to activate it. In my experience all the data had been captured, but was not visible until I clicked in the window.
I just did some experimentation but was not able to reproduce this.
Would you mind providing instructions I can follow to produce the fault @weshowe?