Error in port monitor in Arduino IDE 2.1.1

Development Tools IDE 2.x
1

Hello everyone! I'm facing a very serious issue. I opened Arduino IDE, connected my Arduino Uno, and encountered this error, even though everything was working fine before. I tried reinstalling Arduino IDE, but the problem persists.

IMG_20240330_233420
IMG_20240330_233420783×266 63.2 KB

2

Hi @dewex. The error is quite mysterious. It is possible that there is more information about the error in the logs that are generated by the IDE. I'm going to ask you to provide those logs.

:exclamation: This procedure is not intended to solve the problem. The purpose is to gather more information.

Please do this:

  1. Select File > Quit from the Arduino IDE menus if it is running.
    All Arduino IDE windows will close.
  2. Start Windows "File Explorer".
  3. Open the Arduino IDE installation folder.
    ⓘ The default installation location is at one of the following paths: 
    • C:\Program Files\Arduino IDE

    • C:\Users\<username>\AppData\Local\Programs\Arduino IDE
      (where <username> is your Windows username)
      :exclamation: If looking for it with your file manager or command line, note that the AppData folder is hidden by default. On Windows "File Explorer", you can make it visible by opening the "View" menu, then checking the box next to "☐ Hidden items".
  4. In the folder listing of the Arduino IDE installation folder, hold the Shift key while clicking the right hand button on the mouse.
  5. From the context menu, click "Open PowerShell window here".
    Windows PowerShell will now open with the current directory set to the Arduino IDE installation folder.
  6. Type the following command:
    & ".\Arduino IDE"
  7. Press the Enter key.
    Debug output should now be printed to the PowerShell window as Arduino IDE starts.
  8. Wait for Arduino IDE to finish starting.
  9. Check to see if the "Port monitor error: EOF" error is shown in Serial Monitor. If not, repeat whatever you did before when it occurred in order to produce the error.
  10. Switch back to the PowerShell window.
  11. Press the Ctrl+Shift+A keyboard shortcut.
    This will select all the text in the PowerShell window.
  12. Press the Ctrl+C keyboard shortcut.
    This will copy the contents of the PowerShell window to the clipboard.
  13. Open a forum reply here by clicking the "Reply" button.
  14. Click the <CODE/> icon on the post composer toolbar.
    This will add the forum's code block markup (```) to your reply to make sure the error messages are correctly formatted.
    Code block icon on toolbar
  15. Press the Ctrl+V keyboard shortcut.
    This will paste the output into the code block.
  16. Move the cursor outside of the code block markup before you add any additional text to your reply.
  17. Click the "Reply" button to post the output.

Please let me know if you have any questions or problems while following those instructions.

1 Like
4

Hello @ptillisch, here's what PowerShell gives me:

only contain ASCII characters
[2096:0331/155246.347:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.348:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.348:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.348:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.348:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.349:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.349:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.349:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.350:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.350:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.352:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.564:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.564:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.565:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.567:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.568:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.568:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.568:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.568:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.569:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.569:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.569:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.569:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.570:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.570:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.570:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.571:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.571:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.571:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.571:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.571:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.572:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.572:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.572:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.572:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.573:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.573:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.573:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.573:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.574:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.574:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.574:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.574:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
[2096:0331/155246.576:ERROR:accelerator_util.cc(24)] The accelerator string can
only contain ASCII characters
2024-03-31T10:52:59.734Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:arduinoOTA@1.3.0"

2024-03-31T10:52:59.736Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"


2024-03-31T10:52:59.737Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:avrdude@6.3.0-arduino17"

2024-03-31T10:52:59.738Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:arduinoOTA@1.3.0"

2024-03-31T10:52:59.739Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"


2024-03-31T10:52:59.740Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:avrdude@6.3.0-arduino17"

2024-03-31T10:52:59.743Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:arduinoOTA@1.3.0"

2024-03-31T10:52:59.744Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"

←[36mINFO←[0m[0163] Required tool                                 ←[36mtool←[0m=
"arduino:avrdude@6.3.0-arduino17"

2024-03-31T10:52:59.754Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:arduinoOTA@1.3.0"
←[36mINFO←[0m[0163] Required tool                                 ←[36mtool←[0m=
"arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"
←[36mINFO←[0m[0163] Required tool                                 ←[36mtool←[0m=
"arduino:avrdude@6.3.0-arduino17"

2024-03-31T10:52:59.789Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:arduinoOTA@1.3.0"

2024-03-31T10:52:59.790Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"

←[36mINFO←[0m[0163] Required tool                                 ←[36mtool←[0m=
"arduino:avrdude@6.3.0-arduino17"

2024-03-31T10:53:00.416Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:arduinoOTA@1.3.0"
←[36mINFO←[0m[0163] Required tool                                 ←[36mtool←[0m=
"arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"
←[36mINFO←[0m[0163] Required tool                                 ←[36mtool←[0m=
"arduino:avrdude@6.3.0-arduino17"

2024-03-31T10:53:00.511Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:arduinoOTA@1.3.0"

2024-03-31T10:53:00.512Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"


2024-03-31T10:53:00.513Z daemon INFO ←[36mINFO←[0m[0163] Required tool
                       ←[36mtool←[0m="arduino:avrdude@6.3.0-arduino17"

2024-03-31T10:53:00.971Z root INFO Starting language server: arduino:avr:uno
2024-03-31T10:53:01.020Z root INFO [hosted-plugin: 4764] PLUGIN_HOST(4764): Plug
inManagerExtImpl/loadPlugin(C:\Users\╤П\AppData\Local\Programs\Arduino IDE\resou
rces\app\plugins\vscode-arduino-tools\extension\dist\bundle)
2024-03-31T10:53:03.364Z daemon INFO ←[36mINFO←[0m[0166] Required tool
                       ←[36mtool←[0m="arduino:arduinoOTA@1.3.0"
←[36mINFO←[0m[0166] Required tool                                 ←[36mtool←[0m=
"arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"
←[36mINFO←[0m[0166] Required tool                                 ←[36mtool←[0m=
"arduino:avrdude@6.3.0-arduino17"
←[36mINFO←[0m[0166] Required tool                                 ←[36mtool←[0m=
"arduino:arduinoOTA@1.3.0"
←[36mINFO←[0m[0166] Required tool                                 ←[36mtool←[0m=
"arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"
←[36mINFO←[0m[0166] Required tool                                 ←[36mtool←[0m=
"arduino:avrdude@6.3.0-arduino17"

2024-03-31T10:53:03.428Z monitor-service INFO starting monitor
2024-03-31T10:53:03.430Z daemon INFO ←[36mINFO←[0m[0166] Required tool
                       ←[36mtool←[0m="arduino:arduinoOTA@1.3.0"
←[36mINFO←[0m[0166] Required tool                                 ←[36mtool←[0m=
"arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"
←[36mINFO←[0m[0166] Required tool                                 ←[36mtool←[0m=
"arduino:avrdude@6.3.0-arduino17"
←[36mINFO←[0m[0166] Starting monitor process                      ←[36mmonitor←[
0m=serial-monitor
←[36mINFO←[0m[0166] Required tool                                 ←[36mtool←[0m=
"arduino:arduinoOTA@1.3.0"
←[36mINFO←[0m[0166] Required tool                                 ←[36mtool←[0m=
"arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"
←[36mINFO←[0m[0166] Required tool                                 ←[36mtool←[0m=
"arduino:avrdude@6.3.0-arduino17"
←[36mINFO←[0m[0166] Adding libraries dir                          ←[36mdir←[0m="
C:\\Users\\╤П\\AppData\\Local\\Arduino15\\libraries" ←[36mlocation←[0m=ide
←[36mINFO←[0m[0166] Adding libraries dir                          ←[36mdir←[0m="
C:\\Users\\╤П\\AppData\\Local\\Arduino15\\packages\\arduino\\hardware\\avr\\1.8.
6\\libraries" ←[36mlocation←[0m=platform
←[36mINFO←[0m[0166] Adding libraries dir                          ←[36mdir←[0m="
c:\\Users\\╤П\\Documents\\Arduino\\libraries" ←[36mlocation←[0m=user

2024-03-31T10:53:03.545Z daemon INFO ←[36mINFO←[0m[0166] Monitor process started
 successfully!         ←[36mmonitor←[0m=serial-monitor

2024-03-31T10:53:03.546Z daemon INFO ←[36mINFO←[0m[0166] sending command
                       ←[36mcommand←[0m="HELLO 1 \"arduino-cli 0.32.3\"" ←[36mmo
nitor←[0m=serial-monitor

2024-03-31T10:53:03.559Z daemon INFO ←[36mINFO←[0m[0166] Required tool
                       ←[36mtool←[0m="arduino:arduinoOTA@1.3.0"
←[36mINFO←[0m[0166] Required tool                                 ←[36mtool←[0m=
"arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"

2024-03-31T10:53:03.560Z daemon INFO ←[36mINFO←[0m[0166] Required tool
                       ←[36mtool←[0m="arduino:avrdude@6.3.0-arduino17"

2024-03-31T10:53:03.565Z daemon INFO ←[36mINFO←[0m[0166] Starting monitor proces
s                      ←[36mmonitor←[0m=serial-monitor

2024-03-31T10:53:03.566Z daemon INFO ←[36mINFO←[0m[0166] Monitor process started
 successfully!         ←[36mmonitor←[0m=serial-monitor

2024-03-31T10:53:03.567Z daemon INFO ←[36mINFO←[0m[0166] sending command
                       ←[36mcommand←[0m="HELLO 1 \"arduino-cli 0.32.3\"" ←[36mmo
nitor←[0m=serial-monitor

2024-03-31T10:53:03.931Z daemon INFO ←[31mERRO←[0m[0167] stopped decode loop: EO
F                      ←[31mmonitor←[0m=serial-monitor
←[36mINFO←[0m[0167] Killing monitor process                       ←[36mmonitor←[
0m=serial-monitor

2024-03-31T10:53:03.932Z daemon INFO ←[31mERRO←[0m[0167] Sent kill signal
                       ←[31merror←[0m="TerminateProcess: Access is denied." ←[31
mmonitor←[0m=serial-monitor
←[31mERRO←[0m[0167] stopped decode loop: EOF                      ←[31mmonitor←[
0m=serial-monitor
←[36mINFO←[0m[0167] Killing monitor process                       ←[36mmonitor←[
0m=serial-monitor
←[31mERRO←[0m[0167] Sent kill signal                              ←[31merror←[0m
="TerminateProcess: Access is denied." ←[31mmonitor←[0m=serial-monitor

2024-03-31T10:53:03.936Z daemon INFO ←[31mERRO←[0m[0167] Waiting for process end
                       ←[31merror←[0m="exit status 2" ←[31mmonitor←[0m=serial-mo
nitor
←[36mINFO←[0m[0167] Monitor process killed                        ←[36mmonitor←[
0m=serial-monitor

2024-03-31T10:53:03.942Z monitor-service WARN failed starting monitor to COM5 us
ing serial
2024-03-31T10:53:04.019Z root ERROR Uncaught Exception:
2024-03-31T10:53:04.020Z root ERROR Error: 13 INTERNAL: Port monitor error: EOF
    at Object.callErrorFromStatus (C:\Users\╤П\AppData\Local\Programs\Arduino ID
E\resources\app\node_modules\@grpc\grpc-js\build\src\call.js:31:19)
    at Object.onReceiveStatus (C:\Users\╤П\AppData\Local\Programs\Arduino IDE\re
sources\app\node_modules\@grpc\grpc-js\build\src\client.js:190:52)
    at Object.onReceiveStatus (C:\Users\╤П\AppData\Local\Programs\Arduino IDE\re
sources\app\node_modules\@grpc\grpc-js\build\src\client-interceptors.js:365:141)

    at Object.onReceiveStatus (C:\Users\╤П\AppData\Local\Programs\Arduino IDE\re
sources\app\node_modules\@grpc\grpc-js\build\src\client-interceptors.js:328:181)

    at C:\Users\╤П\AppData\Local\Programs\Arduino IDE\resources\app\node_modules
\@grpc\grpc-js\build\src\call-stream.js:187:78
    at processTicksAndRejections (node:internal/process/task_queues:78:11)
for call at
    at ServiceClientImpl.makeUnaryRequest (C:\Users\╤П\AppData\Local\Programs\Ar
duino IDE\resources\app\node_modules\@grpc\grpc-js\build\src\client.js:160:30)
    at ServiceClientImpl.enumerateMonitorPortSettings (C:\Users\╤П\AppData\Local
\Programs\Arduino IDE\resources\app\node_modules\@grpc\grpc-js\build\src\make-cl
ient.js:105:19)
    at resp (C:\Users\╤П\AppData\Local\Programs\Arduino IDE\resources\app\node_m
odules\arduino-ide-extension\lib\node\monitor-service.js:346:20)
    at new Promise (<anonymous>)
    at MonitorService.portMonitorSettings (C:\Users\╤П\AppData\Local\Programs\Ar
duino IDE\resources\app\node_modules\arduino-ide-extension\lib\node\monitor-serv
ice.js:345:28)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
2024-03-31T10:53:04.024Z daemon INFO ←[31mERRO←[0m[0167] Waiting for process end
                       ←[31merror←[0m="exit status 2" ←[31mmonitor←[0m=serial-mo
nitor
←[36mINFO←[0m[0167] Monitor process killed                        ←[36mmonitor←[
0m=serial-monitor

2024-03-31T10:53:10.226Z daemon INFO ←[36mINFO←[0m[0173] Required tool
                       ←[36mtool←[0m="arduino:arduinoOTA@1.3.0"

2024-03-31T10:53:10.227Z daemon INFO ←[36mINFO←[0m[0173] Required tool
                       ←[36mtool←[0m="arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"


2024-03-31T10:53:10.228Z daemon INFO ←[36mINFO←[0m[0173] Required tool
                       ←[36mtool←[0m="arduino:avrdude@6.3.0-arduino17"

2024-03-31T10:53:10.249Z daemon INFO ←[36mINFO←[0m[0173] Required tool
                       ←[36mtool←[0m="arduino:arduinoOTA@1.3.0"
←[36mINFO←[0m[0173] Required tool                                 ←[36mtool←[0m=
"arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"

2024-03-31T10:53:10.250Z daemon INFO ←[36mINFO←[0m[0173] Required tool
                       ←[36mtool←[0m="arduino:avrdude@6.3.0-arduino17"

2024-03-31T10:53:10.261Z daemon INFO ←[36mINFO←[0m[0173] Required tool
                       ←[36mtool←[0m="arduino:arduinoOTA@1.3.0"
←[36mINFO←[0m[0173] Required tool                                 ←[36mtool←[0m=
"arduino:avr-gcc@7.3.0-atmel3.6.1-arduino7"

2024-03-31T10:53:10.262Z daemon INFO ←[36mINFO←[0m[0173] Required tool
                       ←[36mtool←[0m="arduino:avrdude@6.3.0-arduino17"
5

I see the relative part of the logs here:

Unfortunately it doesn't give me any clue about the cause of the error. I didn't find any other reports of this "Port monitor error: EOF" error.

I see you are using a very outdated version of Arduino IDE. Is there a specific reason you are using version 2.1.1 instead of the latest version 2.3.2? If not, please update to 2.3.2 and check if the problem still occurs. Although I don't have any specific reason to think the problem is caused by the version of Arduino IDE you are using, there have been many bug fixes and enhancements to Arduino IDE since 2.1.1 and it is possible that one of them might have resolved the problem you are experiencing.

I notice that in the screenshot you shared in post #1, the error message is for the COM13 port, but in the logs it is COM5:

Do you have an explanation for that? Do you have a board on COM5 and another on COM13? I don't have any specific reason to think this is related to the problem, but I am grasping at straws since I don't have an idea of the cause.

6

I have the same problem, I also work with 2,1,1, but it worked fine until recently.
If I put the serial monitor of version 1,X,X it works correctly. even if you have loaded the sketch with 2,1,1. and stay open.
The two original boards that I have do the same. I'll send you the link to the error.
I don't work with the latest version since I'm running Windows 7 and the latest versions give me an error when I load them, I guess it's because they need Windows 10.

FQBN: arduino:avr:uno
Using board 'uno' from platform in folder: C:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6
Using core 'arduino' from platform in folder: C:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6

Detectando las librerías usadas...
"C:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7/bin/avr-g++" -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -flto -w -x c++ -E -CC -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10607 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR "-IC:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino" "-IC:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\variants\standard" "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688\sketch\grabador.ino.cpp" -o nul
Generating function prototypes...
"C:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7/bin/avr-g++" -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -flto -w -x c++ -E -CC -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10607 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR "-IC:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino" "-IC:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\variants\standard" "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688\sketch\grabador.ino.cpp" -o "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688\preproc\ctags_target_for_gcc_minus_e.cpp"
"C:\Users\Trini Vilella\AppData\Local\Arduino15\packages\builtin\tools\ctags\5.8-arduino11/ctags" -u --language-force=c++ -f - --c++-kinds=svpf --fields=KSTtzns --line-directives "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688\preproc\ctags_target_for_gcc_minus_e.cpp"
Compilando el sketch...
"C:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7/bin/avr-g++" -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -MMD -flto -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10607 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR "-IC:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino" "-IC:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\variants\standard" "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688\sketch\grabador.ino.cpp" -o "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688\sketch\grabador.ino.cpp.o"
Compilando librerías...
Compilando el núcleo...
Using precompiled core: C:\Users\Trini Vilella\AppData\Local\Temp\arduino\cores\arduino_avr_uno_36409e977deb2eafdde7b1270daa51b6\core.a
Linking everything together...
"C:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7/bin/avr-gcc" -w -Os -g -flto -fuse-linker-plugin -Wl,--gc-sections -mmcu=atmega328p -o "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688/grabador.ino.elf" "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688\sketch\grabador.ino.cpp.o" "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688/..\..\cores\arduino_avr_uno_36409e977deb2eafdde7b1270daa51b6\core.a" "-LC:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688" -lm
"C:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7/bin/avr-objcopy" -O ihex -j .eeprom --set-section-flags=.eeprom=alloc,load --no-change-warnings --change-section-lma .eeprom=0 "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688/grabador.ino.elf" "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688/grabador.ino.eep"
"C:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7/bin/avr-objcopy" -O ihex -R .eeprom "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688/grabador.ino.elf" "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688/grabador.ino.hex"

"C:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7/bin/avr-size" -A "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688/grabador.ino.elf"
El Sketch usa 1626 bytes (5%) del espacio de almacenamiento de programa. El máximo es 32256 bytes.
Las variables Globales usan 192 bytes (9%) de la memoria dinámica, dejando 1856 bytes para las variables locales. El máximo es 2048 bytes.
"C:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/bin/avrdude" "-CC:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/etc/avrdude.conf" -v -V -patmega328p -carduino "-PCOM9" -b115200 -D "-Uflash:w:C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688/grabador.ino.hex:i"

avrdude: Version 6.3-20190619
 Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
 Copyright (c) 2007-2014 Joerg Wunsch

 System wide configuration file is "C:\Users\Trini Vilella\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/etc/avrdude.conf"

 Using Port : COM9
 Using Programmer : arduino
 Overriding Baud Rate : 115200
 AVR Part : ATmega328P
 Chip Erase delay : 9000 us
 PAGEL : PD7
 BS2 : PC2
 RESET disposition : dedicated
 RETRY pulse : SCK
 serial program mode : yes
 parallel program mode : yes
 Timeout : 200
 StabDelay : 100
 CmdexeDelay : 25
 SyncLoops : 32
 ByteDelay : 0
 PollIndex : 3
 PollValue : 0x53
 Memory Detail :

 Block Poll Page Polled
 Memory Type Mode Delay Size Indx Paged Size Size #Pages MinW MaxW ReadBack
 ----------- ---- ----- ----- ---- ------ ------ ---- ------ ----- ----- ---------
 eeprom 65 20 4 0 no 1024 4 0 3600 3600 0xff 0xff
 flash 65 6 128 0 yes 32768 128 256 4500 4500 0xff 0xff
 lfuse 0 0 0 0 no 1 0 0 4500 4500 0x00 0x00
 hfuse 0 0 0 0 no 1 0 0 4500 4500 0x00 0x00
 efuse 0 0 0 0 no 1 0 0 4500 4500 0x00 0x00
 lock 0 0 0 0 no 1 0 0 4500 4500 0x00 0x00
 calibration 0 0 0 0 no 1 0 0 0 0 0x00 0x00
 signature 0 0 0 0 no 3 0 0 0 0 0x00 0x00

 Programmer Type : Arduino
 Description : Arduino
 Hardware Version: 3
 Firmware Version: 4.4
 Vtarget : 0.3 V
 Varef : 0.3 V
 Oscillator : 28.800 kHz
 SCK period : 3.3 us

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.00s

avrdude: Device signature = 0x1e950f (probably m328p)
avrdude: reading input file "C:\Users\Trini Vilella\AppData\Local\Temp\arduino\sketches\00168FBA5FCF04EFD50B348D2049E688/grabador.ino.hex"
avrdude: writing flash (1626 bytes):

Writing | ################################################## | 100% 0.27s

avrdude: 1626 bytes of flash written

avrdude done.

Thank you.

You will tell me
Javier Valero

7

This was the key information that allowed me to reproduce this mysterious problem.

The Serial Monitor feature of Arduino IDE 2.x is only a graphical user interface. The actual communication with the Arduino board via the computer's serial port is handled by a helper tool named "serial-monitor".

I found that, starting from version 0.14.0, serial-monitor is incompatible with Windows 7. This is the cause of the "Port monitor error: EOF " error when attempting to use the Arduino 2.x Serial Monitor on a Windows 7 machine.

On startup, Arduino IDE checks to see if a new version of serial-monitor is available. If so, it automatically installs it. So for this reason, the incompatible version was automatically installed as soon as serial-monitor version 0.14.0 was released.

There are several possible workarounds for this problem. I'll describe both of them below. You can pick whichever one you prefer.

Use Arduino IDE 1.8.19

I know you already discovered this workaround @xvalero55, but I'll mention it for the benefit of @dewex and anyone else who is experiencing the problem and finds this thread during their research for a solution.

Arduino IDE 1.8.19 can be downloaded from the links listed here:

Update Operating System

Windows 7 was retired 4.5 years ago. Microsoft no longer provides security updates for the operating system. So it is a good idea to update your operating system.

If your computer can't support a newer version of Windows, or if you refuse to use the newer versions, you should consider using the excellent free open source Linux operating system. This operating system performs very well even on older or lower spec computers.

Use Compatible serial-monitor Version

As I mentioned above, the incompatibility was introduced in version 0.14.0 of the serial-monitor tool. This means if we can make Arduino IDE use a version of serial-monitor older than 0.14.0 (i.e., 0.13.0) then the problem will be solved.

As I explained previously, Arduino IDE will automatically update the tool if it discovers that a newer version is available than the one that is currently installed. So we must trick Arduino IDE into thinking the 0.13.0 installation is always newer than the latest version of serial-monitor. It determines the version of the tool from the name of the installation folder. So we only need to rename the serial-monitor 0.13.0 installation folder to a very high version number.

I'll provide instructions you can follow to do that:

  1. Select File > Quit from the Arduino IDE menus if it is running.
    All Arduino IDE windows will close.
  2. Rename the 0.13.0 folder at the following path on your hard drive to 999.999.999:
    C:\Users\<username>\AppData\Local\Arduino15\packages\builtin\tools\serial-monitor\0.13.0\
    (where <username> is your Windows username)
    :exclamation: If looking for it with your file manager or command line, note that the AppData folder is hidden by default. On Windows "File Explorer", you can make it visible by opening the "View" menu, then checking the box next to "☐ Hidden items".
  3. Start Arduino IDE.

You should now find that you can use Serial Monitor without encountering that "Port monitor error: EOF " error.

If you installed Arduino IDE recently then Arduino IDE will never have installed version 0.13.0 of serial-monitor and so you will not find the C:\Users\<username>\AppData\Local\Arduino15\packages\builtin\tools\serial-monitor\0.13.0\ when following step (3) of the instructions above. In this case it will be necessary to install that version of serial-monitor. I'll provide instructions for doing that:

  1. Create a folder named 999.999.999 under the following path on your hard drive:
    C:\Users\<username>\AppData\Local\Arduino15\packages\builtin\tools\serial-monitor\
    (where <username> is your Windows username)
    :exclamation: If looking for it with your file manager or command line, note that the AppData folder is hidden by default. On Windows "File Explorer", you can make it visible by opening the "View" menu, then checking the box next to "☐ Hidden items".
  2. Click the following link to open the page of the 0.13.0 release in serial-monitor's GitHub repository:
    https://github.com/arduino/serial-monitor/releases/tag/v0.13.0
  3. Click the "serial-monitor_v0.13.0_Windows_64bit.zip" link you will see under the "Assets" section of that page.
    A download of the ZIP file of the serial-monitor tool will start.
  4. Wait for the download to finish.
  5. Extract the downloaded file.
  6. Move the serial-monitor.exe file from the extracted folder to the folder you created in step (1).
    :exclamation: The installation must have this folder structure:
    C:\Users\<username>\AppData\Local\Arduino15\packages\builtin\tools\
├── serial-monitor\
│   ├── 999.999.999\
│   │   └── serial-monitor.exe
│   ...
...
9

Thank you so much for that simple solution which works perfectly. I've been bashing my head over it for days. The weird thing is the monitor v 0.14 worked perfectly well with my Teensy 4.1 but I got the 'Port monitor error: EOF' when connected to an STM32 based 'Black Pill' board, which threw me off the scent a little.

10

You are welcome. I'm glad it is working again now.

I mentioned in my reply how the Serial Monitor component of Arduino IDE 2.x is only a GUI for displaying data received from the helper tool, and for passing data input by the user to the tool.

This separation of the low level capabilities into a separate tool was done intentionally in order to support a "pluggable monitor" system, where platform developers can create their own custom tools to handle any imaginable type of communication between the computer and the Arduino board. This means that the "Serial Monitor" name of the Arduino IDE component is greatly underselling the feature since this can now be used for any type of communications; not communication over a serial port alone.

A big part of the motivation behind the creation of this system was that creator of the Teensy boards, Paul Stoffregen had found the Arduino IDE 1.x Serial Monitor to not meet their requirements and wrote a replacement. This was one of the things that made it necessary for Paul to maintain a modified version of the open source Arduino IDE 1.x ("Teensyduino") in order to provide Arduino framework support to users of the Teensy boards. One of the design goals for the Arduino IDE 2.x project was to make the tool flexible and powerful enough that it could accommodate the emerging requirements of the ever expanding ecosystem of Arduino boards, both for Arduino's own official boards as well as the huge number of 3rd party boards such as the Teensy line.

So Paul Stoffregen actually wrote their own monitor tool (which is called teensy-monitor) for Arduino IDE 2.x and that tool is used by the Arduino IDE 2.x Serial Monitor when you have selected the "Teensy" protocol ports used by Teensy boards. This is the reason why the "Port monitor error: EOF" error will only occur when Serial Monitor is used with a "Serial" protocol port, which causes the now Windows 7 incompatible serial-monitor tool to be used.

11

Thanks for the explanation. Makes perfect sense.

1 Like
12

@ptillisch , thank you very much! This solution helped me, and now the port monitor is working correctly without errors. Thanks again!

13

You are welcome. It is unfortunate that it took us a long time to figure out the cause of the problem, but at least we have a solution now.

Regards,
Per

1 Like
14

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