Hi,
The Attribute properties for Service Changed Characteristic in GATT seems wrong on DA1458x SDK.
I checked this issue using Protocol Air sniffer and I found that attribute properties are set to "Read / Indicate". Regarding the SIG specification, this attribute properties shall be set to "Indicate".
We would like fix this, but I think this characteristic (As an server role) on DA1458x SDK is object code and we can not edit it. (Client side for this service is opened and editable.)
Is it coded as an object in SDK? Could we change this property by our selves?
Thank you very much for your cooperation.
Best Regards,
CD
Device:
Hi CD,
From the 4.0 spec on page 1944 the characteristic properties of the service changed characteristic is 0x26 which corresponds to page 1898 (table 3.5) (READ, INDICATE, WRITE_NO_RESPONSE). Also yes, the Generic attribute service is instantiated by the ROM code, you wont be able to change permissions of the Service Changed characteristic. You can disable the read permission, although the permission will be there and the characteristic will be visible as readable but no client will be able to read it. You can try and place the following code in the user_app_on_set_dev_config_complete().
void app_disable_svc_changed_read(void)
{
uint16_t hdl;
uint8_t uuid_len;
uint16_t uuid[8];
hdl = 1;
while((attmdb_att_get_uuid(hdl, &uuid_len, (uint8_t *)uuid)) != ATT_ERR_INVALID_HANDLE)
{
if ((uuid[0] == ATT_CHAR_SERVICE_CHANGED) && (uuid_len == 2))
{
attmdb_att_set_permission(hdl, PERM(RD, DISABLE));
break;
}
hdl++;
}
}
Thanks MT_dialog
Hi MT,
Thank you very much for your reply.
Unfortunately, 0x26 is typo and there is the Errata document for it (ESR05 - ERRATA SERVICE RELEASE TO BLUETOOTH® SPECIFICATIONS ). Please see Erratum 3833, page 68 on this document.
This characteristic seems Read-Only. Version 4.1 or 4.2 document has been updated for this... I think this is not a big issue for actual communication, but it is out of specification. I hope the ROM on the next chip fix this.
Is it possible to provide simple patch file for this?? (I don't know whether it is easy or not, though...)
Best Regards,
CD
Hi CD,
Thanks for the indication. You 're right, just saw the Erratum and the correction. I will check with the team and let you know.
Thanks MT_dialog
Hi CD,
The property of the characteristic will be fixed in future releases, a patch isn't available since the specific issue hasn't significant impact to the applications.
Thanks MT_dialog
Hi MT,
I understand it.
Thank you so much for your reply and support.
Please close this topic.
Best,
CD