Grand Central M4 Serial Port missing at run-time on MacOS A

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willp1203
 
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Joined: Tue Sep 04, 2012 6:34 pm

Grand Central M4 Serial Port missing at run-time on MacOS A

Post by willp1203 »

Many of my projects use the Arduino IDE serial monitor developed on my Mac (10.13.6). I simply want to replace my Mega 2560 with a "Metro M4 Grand Centra (MM4GC)l" and keep coding. But, the Arduino IDE serial monitor that I use for debugging statement is no longer working because the serial port goes missing at the moment of run-time (okay for uploading). BTW, my setup works great for many boards other than this MM4GC board.

Said another way, after uploading code from the Arduino IDE to my Grand Central board, the serial port used for programming disconnects and I'm expecting the Arduino IDE serial port to be "available" at the beginning of run-time - it doesn't, it's missing and the program fails with "Error opening serial port /dev/...".

I've troubleshot all related symptoms and everything I've done appears to be in good working order (UF2 bootloader, uploading, reflashing bootloader, GCM4BOOT drive, USB serial drivers)... except the Serial port is not present at run-time.

Q: What bootloader should I be using to work with the Arduino IDE and expect the serial monitor port to work?

FYI: My board/bootload is:
UF2 Bootloader v1.23.1-adafruit.1-88-g797305f SFHWRO
Model: Grand Central M4 Express
Board-ID: SAMD51P20A-GrandCentral-v0

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Franklin97355
 
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Re: Grand Central M4 Serial Port missing at run-time on Mac

Post by Franklin97355 »

After the upload do you check the tools > ports menu? Is there a different port associated with the GC?

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willp1203
 
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Re: Grand Central M4 Serial Port missing at run-time on Mac

Post by willp1203 »

hi @franklin97355
Q: You asked: "After the upload do you check the tools > ports menu? Is there a different port associated with the GC?"
A: I can make this serial port appear each time I double-tap the reset button (e.g. enter programming mode) /dev/cu.usbmodem1411. Once upload and verify are 100% complete, this serial port goes away (no longer listed in Tools->Port) and I get "Error opening serial port /dev/cu.usbmodem1411".

I'm not certain, but it seems as though the bootloader I'm using is not the right one for the Arduino IDE. In all the information about the bootload topic, it's unclear to me what bootloader is supposed to be on the board in order to communicate with the IDE's serial monitor at runtime for the Mac. I see several threads where this exact same issue has been trouble for the PC and it is simply a matter of specifying one serial port for runtime and another for uploading. For the Mac, the uploading port is fine, but the runtime port is missing??

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willp1203
 
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Re: Grand Central M4 Serial Port missing at run-time on Mac

Post by willp1203 »

Success!
Problem found and fixed.

I have defective Metro M4 Grand Central with the crystal oscillator upside down. I repaired the board (see pic) with my hot air station and it works correctly.
The picture shows the oscillator is upside down. Board will work during bootloader or programming, but will not operate at full speed properly at run-time.

When the defect is present, I suspect the processor is using the internal oscillator at a much lower speed (e.g. 8MHz). But, once the external oscillator is correctly placed on the board, the external oscillator is used to allow the processor to run at full speed (120MHz) -- thus eliminating the serial port problem at run-time. That's a tricky problem to find.

Thank you to the members in these posts who had the same issue but expressed problems with the serial port at run-time using different ways.
viewtopic.php?f=63&t=150581
viewtopic.php?f=63&t=150320
Left - Picture shows the oscillator is upside down (board crippled but functions).  Right - Oscillator is placed correctly an board runs at full speed - fixed.
Left - Picture shows the oscillator is upside down (board crippled but functions). Right - Oscillator is placed correctly an board runs at full speed - fixed.
GrandCentral_oscillator_upside-down.jpg (556.7 KiB) Viewed 239 times

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Franklin97355
 
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Re: Grand Central M4 Serial Port missing at run-time on Mac

Post by Franklin97355 »

Thank you for post the problem and solution. This and the other post will help others in the future if they have the same problem (I hope we got all the bad ones out of the system)

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