1. Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
    Dismiss Notice

How to fix: Serial Port 'COM3' not found.

Discussion in 'Arduino' started by PamieBeverly, Feb 25, 2016.

  1. PamieBeverly

    PamieBeverly New Member

    Joined:
    Jul 14, 2014
    Messages:
    5
    Likes:
    0
    Location:
    Quezon City, Philippines
    My arduino is working on my pc until I tried to connect my other Arduino on my pc, and an error occured, and showed below: Serial Port 'COM3' not found. Did you select the right one from the Tools > Serial Port menu? Thus, the Serial Port on the Tools menu is not highlighted. Can someone who is expert or well-known in Arduino help me with this problem? Please I really need it as soon as possible, Thank you. :)
     
  2. MrAl

    MrAl Well-Known Member Most Helpful Member

    Joined:
    Sep 7, 2008
    Messages:
    11,029
    Likes:
    951
    Location:
    NJ
    Hi Pamie,

    Welcome to the ETO forum.

    I can offer a couple suggestions but would also have to ask a few questions too.

    First, does this happen with only one board or all your Arduino boards?
    Also, are you trying to use a USB 3.0 port or a USB 2.0 port?
    Another question, what kind of Ardu board are you using (Uno, etc.)?

    I ask about the port type because some of the Arduino's do not work in some USB 3.0 ports but work fine in USB 2.0 ports.

    I can offer a suggestion or two for now...

    You can try unplugging the board then plugging it back in.
    You can try closing down the IDE, then restarting it.

    You can go into Device Manager and see if your Arduino is listed there, or at least the COM 3 port. This helps troubleshoot because you'll see the listing change when you plug in the board, if it is working properly. If it is not working properly, then you will see something different and that will tell you right away that you have to unplug it and plug it back in for example
    If using a USB hub, that may need to be unplugged and plugged back in again too, and even might need to reboot the computer to get it to work properly. Sometimes hubs can work for some things but not other things until they are unplugged and plugged back in again.
    Last resort, reboot the computer.

    If nothing ever helps with a given board it could be a bad board too, or a fake USB to RS232 converter chip on board that Windows has recognized as fake and shut it down. This should not happen any more but i guess it is always a possibility. The only thiing i can think of here is to try the board in a computer with another operating system like maybe XP.

    If you give more details about what you are using and what exactly you are experiencing, maybe someone here can help more. It might also help to know where you purchased the board from.

    In the mean time, good luck with it.
     
  3. Ian Rogers

    Ian Rogers Super Moderator Most Helpful Member

    Joined:
    Mar 28, 2011
    Messages:
    9,165
    Likes:
    910
    Location:
    Rochdale UK
    ONLINE
    USB ports will always enumerate as a different COM port... So if you use USB socket A (enumerated as COM3 ) then use USB socket B... This will not be COM3...

    If you right click "My Computer" and look in device manager... All valid COM ports will be listed!!
     
  4. dave

    Dave New Member

    Joined:
    Jan 12, 1997
    Messages:
    -
    Likes:
    0


     
  5. PamieBeverly

    PamieBeverly New Member

    Joined:
    Jul 14, 2014
    Messages:
    5
    Likes:
    0
    Location:
    Quezon City, Philippines

    Thank you for replying MrAl.

    Actually what I have here is 3 Arduino, whereas; I have 2 clone Arduino, both are ATMEGA644, bought at the same store, but only 1 was working. And the other one is a genuine Arduino but not working. So it only happens in my 2 arduino.

    Now, I do not know if it is USB 3.0 or USB 2.0 the port I am using. The ardu board I am using is MEGA2560,.

    I already tried few of your suggestions, such unplugging ang plugging back the board, restarting the IDE, restarting my pc. But wheb I checked my device manager, the COM3 port does not appear. Do you think, it isbthe problem?
     
  6. PamieBeverly

    PamieBeverly New Member

    Joined:
    Jul 14, 2014
    Messages:
    5
    Likes:
    0
    Location:
    Quezon City, Philippines
    Mr Ian Rogers,

    I checked my device manager, but no COM ports are listed.
     
  7. Les Jones

    Les Jones Well-Known Member

    Joined:
    May 15, 2015
    Messages:
    1,446
    Likes:
    187
    Location:
    Lancashire UK
    You should get a display like this. When you first open Device manager you will need to click on the triangle to the left of "Ports (COM & LPT)" to show all items of that type.

    Screen Shot 02-26-16 at 08.40 AM 001.PNG
    Les.
     
  8. Ian Rogers

    Ian Rogers Super Moderator Most Helpful Member

    Joined:
    Mar 28, 2011
    Messages:
    9,165
    Likes:
    910
    Location:
    Rochdale UK
    ONLINE
    Then you need to reboot the USB service.... Reboot every USB controller!
     
  9. djsfantasi

    djsfantasi Member

    Joined:
    Mar 15, 2011
    Messages:
    161
    Likes:
    21
    Location:
    Metro Boston
    In the Arduino IDE, go to Tools | Port. You'll see COM3: and likely another port labeled with the type of Arduino you've connected. Click on that port and then retry!

    Happens all the time (port changes and the IDE won't find it without this process).
     
  10. Ian Rogers

    Ian Rogers Super Moderator Most Helpful Member

    Joined:
    Mar 28, 2011
    Messages:
    9,165
    Likes:
    910
    Location:
    Rochdale UK
    ONLINE
    If it isn't showing in device manager, the IDE will never find it!!!

    Try rebooting the computer... If the device manager doesn't see it, then the USB controller has crashed!!! If this be the case... Check the current consumption of the arduino that caused the crash...
     
  11. MrAl

    MrAl Well-Known Member Most Helpful Member

    Joined:
    Sep 7, 2008
    Messages:
    11,029
    Likes:
    951
    Location:
    NJ
    Hi,

    You are very welcome Pamie :)

    Well, from what you have said so far (one is working and the other two are not working) then it sounds like, on the surface of it, that two of the boards are defective.

    There's one other possibility, and that is that the one 'good' board has a different USB controller chip than the other two (no matter where they came from) and those two controller chips dont work well with USB 3.0 and you are using USB 3.0 ports. That would mean the other two boards would work if plugged into a USB 2.0 port. It's hard to say for sure though, but obviously something is wrong and it's either the two boards or the two controller chips or the USB port. You could also try another USB port.
    Note that most USB 3.0 ports have a blue colored plastic insert in the port jack, while USB 2.0 ports are usually red. The USB 3.0 ports may also appear to be 'upside down' as compared to the USB 2.0 ports. You could check those details.
    There is also the possibility that the USB controller on the Arduino board needs reflashing, but you'd have to check the Arduino site for information on that, and even if your boards have a chip that can be reflashed (with the firmware).

    All things considered so far, the best bet for you i would say is to try those three cards in another computer making sure to note which one works in your original computer and which two dont. You dont have to install the IDE, just look in Device Manager as suggested elsewhere. Look for an added port when you plug it in, or the name of the board in Device Manager.
    This will tell you pretty much for sure if the boards are really bad or just dont work with your computer's port controller for some reason.
    It might be best to test them one at a time too, so after you test one, unplug the board and plug the next one it.
    Also, use a known good USB cable for all the tests.

    Another thing i would ask is, do the two bad boards power up? Can you see LED's lit? Do they have the notorious 'Blink' program loaded in them (you'd see one LED blinking on and off)?

    I wish you all the luck, and hope you get this resolved. You may have to send the boards back if it turns out that they are really bad. Can you mention where you purchased them? If you dont want to that's ok too, but thought it might be worthwhile knowing that too.
     
    Last edited: Feb 26, 2016
  12. granddad

    granddad Active Member

    Joined:
    Jan 18, 2015
    Messages:
    750
    Likes:
    75
    Location:
    Worcestershire UK
    Lots on the web re counterfeit FTDI usb chips , these boards got FTDI..
     

Share This Page