Bluetoothctl: "write" command only send one byte.

Bluetoothctl: "write" command only send one byte.

[Manuel Masiello]

Hello everybody,

I write to the community because I have a problem using Bluetoothctl.
I am looking to write in an attribute with the gatt command "Write".

Here is my command line operation suite:

$ bluetoothctl

[bluetooth]# power on
[bluetooth]# connect A6:41:29:67:30:ED
[my_device]# menu gatt
[my_device]# select-attribute 
/org/bluez/hci0/dev_A6_41_29_67_30_ED/service0034/char0035
[my_device:/service0034/char0035]# write 0x41 0x54 0x2b 0x4e 0x69 0x6d 
0x70 0x00

This is where I have a problem. I never get an error message but the BLE 
device only receive the 1st byte 0x41.
However, using Android applications like LightBlue or nRF Connect, it 
receives correctly what I seek sent.
I scanned the net without finding an answer. I do not really understand 
why it does not work ...


For information:
Linux version 4.13.0-36-generic (buildd@lcy01-amd64-017) (gcc version 
7.2.0 (Ubuntu 7.2.0-8ubuntu3.2)) #40-Ubuntu SMP Fri Feb 16 20:07:48 UTC 2018

I only have "Bluetoothctl" to do the job because the Alpine Linux 
distribution contains nothing else:
https://pkgs.alpinelinux.org/contents?file=&path=&name=bluez&branch=edge&repo=main&arch=x86

Is there anyone who can help me find my mistake?


Best regards,
Manuel

Re: Bluetoothctl: "write" command only send one byte.

[Szymon Janc]

Hi,

On Thursday, 8 March 2018 18:11:26 CEST Manuel Masiello wrote:
> Hello everybody,
> 
> I write to the community because I have a problem using Bluetoothctl.
> I am looking to write in an attribute with the gatt command "Write".
> 
> Here is my command line operation suite:
> 
> $ bluetoothctl
> 
> [bluetooth]# power on
> [bluetooth]# connect A6:41:29:67:30:ED
> [my_device]# menu gatt
> [my_device]# select-attribute
> /org/bluez/hci0/dev_A6_41_29_67_30_ED/service0034/char0035
> [my_device:/service0034/char0035]# write 0x41 0x54 0x2b 0x4e 0x69 0x6d
> 0x70 0x00
> 
> This is where I have a problem. I never get an error message but the BLE
> device only receive the 1st byte 0x41.
> However, using Android applications like LightBlue or nRF Connect, it
> receives correctly what I seek sent.
> I scanned the net without finding an answer. I do not really understand
> why it does not work ...
> 
> 
> For information:
> Linux version 4.13.0-36-generic (buildd@lcy01-amd64-017) (gcc version
> 7.2.0 (Ubuntu 7.2.0-8ubuntu3.2)) #40-Ubuntu SMP Fri Feb 16 20:07:48 UTC 2018
> 
> I only have "Bluetoothctl" to do the job because the Alpine Linux
> distribution contains nothing else:
> https://pkgs.alpinelinux.org/contents?file=&path=&name=bluez&branch=edge&rep
> o=main&arch=x86
> 
> Is there anyone who can help me find my mistake?

Digging out this unanswered question as people seems to ask this on IRC too.
You need to use quotes:
write "0x41 0x54 0x2b 0x4e 0x69 0x6d 0x70 0x00"

And yeah, this could be fixed to accept also 0x01020304 and no quotes for 
conveniense:-)

-- 
pozdrawiam
Szymon Janc

Re: Bluetoothctl: "write" command only send one byte.

[Manuel Masiello]

Hello,
Thank you for your reply. This question dates a bit.
I remember having to change my code a lot to make it work but I do not 
know why it works now.
I do not have any more odds in my python code:

'write 0x' + ' 0x'.join(sString.encode('hex') for sString in (sString + 
'\0'))

Best,
Manuel

On 06/14/2018 12:54 AM, Szymon Janc wrote:
> Hi,
>
> On Thursday, 8 March 2018 18:11:26 CEST Manuel Masiello wrote:
>> Hello everybody,
>>
>> I write to the community because I have a problem using Bluetoothctl.
>> I am looking to write in an attribute with the gatt command "Write".
>>
>> Here is my command line operation suite:
>>
>> $ bluetoothctl
>>
>> [bluetooth]# power on
>> [bluetooth]# connect A6:41:29:67:30:ED
>> [my_device]# menu gatt
>> [my_device]# select-attribute
>> /org/bluez/hci0/dev_A6_41_29_67_30_ED/service0034/char0035
>> [my_device:/service0034/char0035]# write 0x41 0x54 0x2b 0x4e 0x69 0x6d
>> 0x70 0x00
>>
>> This is where I have a problem. I never get an error message but the BLE
>> device only receive the 1st byte 0x41.
>> However, using Android applications like LightBlue or nRF Connect, it
>> receives correctly what I seek sent.
>> I scanned the net without finding an answer. I do not really understand
>> why it does not work ...
>>
>>
>> For information:
>> Linux version 4.13.0-36-generic (buildd@lcy01-amd64-017) (gcc version
>> 7.2.0 (Ubuntu 7.2.0-8ubuntu3.2)) #40-Ubuntu SMP Fri Feb 16 20:07:48 UTC 2018
>>
>> I only have "Bluetoothctl" to do the job because the Alpine Linux
>> distribution contains nothing else:
>> https://pkgs.alpinelinux.org/contents?file=&path=&name=bluez&branch=edge&rep
>> o=main&arch=x86
>>
>> Is there anyone who can help me find my mistake?
> Digging out this unanswered question as people seems to ask this on IRC too.
> You need to use quotes:
> write "0x41 0x54 0x2b 0x4e 0x69 0x6d 0x70 0x00"
>
> And yeah, this could be fixed to accept also 0x01020304 and no quotes for
> conveniense:-)
>