Update: I downloaded the LightBlue app from the Apple Store. The app
allows you to connect to a GATT server and select available services to
interact with. My notification characteristic showed up properly with an
initial value of 0x00 and a CCC value of 0. But when attempted to
register with the notification I saw this error from my bluetoothd output:
bluetoothd[8754]: Refusing storage path for private addressed device
/org/bluez/hci0/dev_59_F2_63_47_1D_90
bluetoothd[8754]: Unable to get ccc storage path for device
bluetoothd[8754]: attrib/gattrib.c:g_attrib_ref() 0xa073bd8: ref=3
bluetoothd[8754]: attrib/gattrib.c:g_attrib_unref() 0xa073bd8: ref=2
Unfortunately, I do not know the command LightBlue was sending to set
the CCC, but I figured this might be a clue for someone.
Am I not properly setting up the notification characteristic? I followed
the same logic as the power level characteristic setup in
profiles/proximity/reporter.c register_tx_power().
Thanks
Nate
On 10/14/14 11:54 AM, Nathan Jozwiak wrote:
Hi all,
I'm trying to send a notification to a client when a characteristic
value is updated by the server.
Here is the characteristics creation in the GATT server:
/* Notification characteristic */
bt_uuid16_create(&uuid, GATT_CHARAC_UUID);
atval[0] = GATT_CHR_PROP_READ | GATT_CHR_PROP_NOTIFY;
put_le16(h + 1, &atval[1]);
put_le16(UUID_NOTIFY, &atval[3]);
attrib_db_add(adapter->adapter, h++, &uuid, ATT_NONE,
ATT_NOT_PERMITTED, atval, 5);
/* Notification value */
bt_uuid16_create(&uuid, UUID_NOTIFY);
ekey_valid_handle = h;
atval[0] = 0x00;
attrib_db_add(adapter->adapter, h++, &uuid, ATT_NONE,
ATT_NOT_PERMITTED, atval, 1);
/* Notification Client Characteristic Config (CCC) */
bt_uuid16_create(&uuid, GATT_CLIENT_CHARAC_CFG_UUID);
atval[0] = 0x00;
attrib_db_add(adapter->adapter, h++, &uuid, ATT_NONE, ATT_NONE,
atval, 1);
I am connecting to the GATT server using the gatttool on another Linux
system.
[CON][00:02:72:C9:5E:0F][LE]> char-desc 0x18
handle: 0x0018, uuid: 2803
handle: 0x0019, uuid: f005
handle: 0x001a, uuid: 2902
[CON][00:02:72:C9:5E:0F][LE]> char-read-hnd 0x1a
Characteristic value/descriptor: 00 01
[CON][00:02:72:C9:5E:0F][LE]> char-read-hnd 0x19
Characteristic value/descriptor: 00
Should the CCC init to 0x01? That doesn't make sense to me. Wouldn't
that indicate the client was already setup for notifications?
I have an application that communicates with bluetoothd over TCP
sockets. So when I send bluetoothd a command it will forward it, my
application will process it, and respond to bluetoothd which will then
update the Notification characteristic value depending on the
success/failure of processing. I then need to notify the client of the
change so it can reread the value to see if the command was successful.
[CON][00:02:72:C9:5E:0F][LE]> char-write-cmd 0x000b 0x1234567890
[CON][00:02:72:C9:5E:0F][LE]> char-read-hnd 0x19
Characteristic value/descriptor: ff
The update of the characteristic value worked fine. But I am using btmon
to monitor traffic between the two devices and I see no messages going
out from the server to the client.
Thanks,
Nate
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Nathan Jozwiak
MapleLeaf Software, Inc.
858-598-4814
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