Bluetooth basic problem with the micro:bit

Apparently, there is no need to connect, before attempting to flash a .hex file.............

So I tried simply flashing, to a paired micro:bit and after 30 seconds or so got the error:

"Flashing unsuccessful  GATT ERROR". I tried several times with different .hex files. All produce the same result.

Can anyone help, please?

And I have resolved it!

I was using the PXT editor which is more sophisticated than the simple Blocks Editor. At the time of making the original post, the default configuration of the PXT editor did not support Bluetooth connection, although the micro:bit would still pair, unless you explicitly loaded the Bluetooth package.

I have now been advised of a "workround" which ensures that you can ALWAYS pair and connect, irrespective of the contents of the current program installed on the micro:bit.

Please contact if you would like details.

This post edited 3 March 2017

This post edited again 07 November 2018 and UNMARKED as "Correct Answer"

Correct Answer now points to the Detailed Instructions on the pairing Workaround in a later post

Hi Neil,

I am trying to pair my microbit to my Samsung, but I'm not getting the pairing message on the microbit. I hold down the A and B buttons , then press the reset on the back for a second and let go. Absolutely nothing happens... could you send me details of the workaround you mentioned?

I just have the microbit connected to a Windows 10 machine, and I flash code successfully to it from Mu.

P.S. Is this what you meant by contact?

Thanks!

Melissa

Hi ksilver.

Melissa - the problem you describe is one step further back from the problem I reported - you can't even put your micro:bit into pairing mode!

I have found the following to be the most reliable method of putting the micro:bit into pairing mode:

press and hold down the A and B buttons. Then press AND HOLD DOWN the reset button. Keep the reset button held down until the pairing message appears.

If this still doesn't work and you are powering the micro:bit connected from USB, try swapping to battery power, or vice-versa. In theory you can have both USB and battery connected at the same time, but I never do - just in case!

If you still can't get the pairing message it's possible that your micro:bit is faulty. Do you have access to anyone local to you who has a micro:bit? They might be able to help.

By the way, unless I am actually flashing the micro:bit, I  run it on battery power - it seems to run cooler that way and I have already had 2 micro:bits fail because of overheating.

Hope this helps!

if you still need the workaround to achieve a connection, then contact again through this post thread - and yes this is what I meant by contact.

Good luck

Neil

Hi, thanks for the reply

I have three microbits, and I've tried it with them all. Literally nothing happens ... I tried them with a battery pack, too, but now I will see if I can get some better quality batteries when I nip out for lunch... hopefully then!

Hi.

We would love to hear about your work around. How you get it to sync everytime.

After we transfered our first Python, the bluetooth sync functionality is gone. The pairing functionality was also gone until we made a block editor program and transfered it by cable. Even though the pairing now works again, we can't transfere programs by Bluetooth.

It seems like the block editor always includes the Bluetooth functionality, where as the python editor doesn't. Is it enough to import the radio module in a python program to the sync functionality back?

Please tell us your work around :-)

/Henrik

Hi Melissa

Any luck?

it's worrying that all 3 micro:bits are showing the same problem!

Have you, by any chance, flashed with a MicroPython script as mentioned by henrikbirkholm?

If so, then you need to reinstate the DFU code, as described here:

https://support.microbit.org/support/solutions/articles/19000026073-how-to-re-instate-bluetooth-after-previously-using-micropython.

Best wishes

Neil

Hi henrikbirkholm

Hello Henrik

Unforunately, installing a MicroPython script ALWAYS destroys the bluetooth pairing ability and the "workround" (courtesy of Joe Finney, Lancaster University) will NOT work with any MicroPython script, I'm afraid.

See here: https://support.microbit.org/support/solutions/articles/19000026073-how-to-re-instate-bluetooth-after-previously-using-micropython

The "workround" is designed to allow flashing (Pairing/synchronising/bonding should work anyway!) with a PXT compliled .Hex file that does not have the Bluetooth module loaded. It shouldn't be necessary with a .Hex file compiled with any other Blocks style editor.

Here is Joe Finney's "workround", which will enable you to flash a .Hex file from the Samsung App:

1. Flash micro:bit with a PXT compiled .HEX file that does not have Bluetooth enabled.
2. Pair micro:bit with phone.
3. Start Samsung micro:bit App
4. Put micro:bit back into pairing mode.
5. DO NOT try to CONNECT to micro:bit from Samsung App - it won't
6. Go straight to FLASH from Samsung App - it should work!

I hope this helps.

Neil

Edited 07 November 2018 and marked as Correct Answer

Very clever - Neil. This worked for me - I was getting the "GATT ERROR" but following your workaround in exactly the given order enable me to upload some previous compiled code for driving a model car from an Andoid bluetooth app.

Tony

Hi tony1tf

Glad it worked for you! - Your project sounds interesting; are you writing it up anywhere?

Neil