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bluezbluetooth-gattbluetoothctl

bluetoothctl creating gatt server - cant write more than one byte

I've added a service and charecteristic with bluetoothctl (bluez v5.64). I have some issues:

  1. I can only write one byte. attempting write "0x11 0x22" results in "Unable to write local attribute /org/bluez/app/service0/chrc0". see below.

  2. I saw in gatt-api I can set mtu when performing read/write, is that option available via bluetoothctl?

  3. not sure why attribute-info is not honored. any idea why?

thanks!

#list-attributes local

Primary Service (Handle 0x0029)
    /org/bluez/app/service0
    00071100-f0d4-469d-afd3-605a6ebbdb13
    Vendor specific
Characteristic (Handle 0x002b)
    /org/bluez/app/service0/chrc0
    0d271100-1111-469d-afd3-605a6ebbdb13
    Vendor specific


[/org/bluez/app/service0/chrc0]# select-attribute 0d271100-1111-469d-afd3-605a6ebbdb13
[/org/bluez/app/service0/chrc0]# write "0x1 0x2"
Unable to write local attribute /org/bluez/app/service0/chrc0
[/org/bluez/app/service0/chrc0]# write "0x3"
[CHG] Attribute /org/bluez/app/service0/chrc0 (Vendor specific) written


attribute-info 0d271100-1111-469d-afd3-605a6ebbdb13
Attribute 0d271100-1111-469d-afd3-605a6ebbdb13 not available
Solution

  • well, looked in the bluetoothctl code. it seems that when creating the charecteristic (register-characteristic) the enter value sets the maximum characteristic length..

    eg.

    [bluetooth]# register-characteristic 0xff12 read,write,notify

    [NEW] Characteristic (Handle 0x0000)

    /org/bluez/app/service0/chrc0

    0xff12

    Unknown

    [/org/bluez/app/service0/chrc0] Enter value: 0x11 0x22 0x33 0x44 0x55

    ..

    [/org/bluez/app/service0/chrc0]# write "0x3 0x6"

    [CHG] Attribute /org/bluez/app/service0/chrc0 (Unknown) written