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CPX serial communication is not working
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CPX serial communication is not working

by oriolboix on Thu Aug 01, 2019 6:39 am

I am working with CPX from 18 months ago, so I am not a new user.

This week I experienced a new problem. One of the CPX used in the last semester classes don’t communicate with Mu. If I save my program it works. But if I save a program with mistakes I haven’t any error message. If my program has print instructions, nothing is printed. An important detail is that my program works with the REPL closed and not with the REPL opened.

I uninstalled and reinstalled the microsoft drivers, installed the latest version of UF2 and the latest version of Mu but there is no change. Finally, I erased the memory of the CPX using the erase UF2. I also tried to connect using Putty instead of Mu but I don’t receive anything.

There is another method to recuperate my CPX communication?


Thanks

oriolboix
 
Posts: 5
Joined: Thu Apr 20, 2017 2:59 am

Re: CPX serial communication is not working

by oriolboix on Sun Aug 04, 2019 2:21 pm

Problem solved!

I have my computer under the table, so it is not easy to connect to the USB ports of the computer box. My screen has two USB ports, so I usually use that to connect my devices. Normally, I connect my microcontrollers to the USB ports in the screen.

Today, I tried again my CPX board but (I don’t know why) I connected it to one of the USB ports in the computer box. It worked fine!

Then, I tried several times. It works correctly when connected directly to the computer and it not works when connected to the screen.

I suspect that, probably, an actualization of the operating system changed the performance of the extended USB ports.

oriolboix
 
Posts: 5
Joined: Thu Apr 20, 2017 2:59 am

Re: CPX serial communication is not working

by kevinjwalters on Tue Aug 06, 2019 2:32 pm

Do you have a group of computers that have the same operating system build and hardware? That would help identify if it's a problem unique to one desktop/monitor or a common problem across all hardware.

I don't know if it's significant but the usb ports on a monitor are typically going to be part of a USB hub - not all devices work with those. If your CPX worked in the past then the Adafruit boards must be ok with them.

kevinjwalters
 
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Joined: Sun Oct 01, 2017 3:15 pm

Re: CPX serial communication is not working

by oriolboix on Wed Aug 07, 2019 4:15 am

I have several computers with the same hardware. I tested in computers with the same screen and with Windows 7 operating systems, in ones with 32-bit version and in others with 64-bits.The same result in all. Curiously, one month ago it works fine.

One colleague explained me another curious case. He uses PIC microcontrollers with PICkit2 and PICkit3 programmers. In the classroom it works fine at the start of the session but later only the back ports of the computer can program. At the middle of the session frontal ports don’t work.

Probably, as you say, USB hubs are not the best way to program microcontrollers.

oriolboix
 
Posts: 5
Joined: Thu Apr 20, 2017 2:59 am

Please be positive and constructive with your questions and comments.