How does one get an internal firmware notification when an external device reads a characteristic?

RE: How does one get an internal firmware notification when an external device reads a characteristic?

Amanda Hsieh — Wed, 26 Aug 2020 05:51:15 GMT

Good to hear the success. You can verify his answer to thank him.

RE: How does one get an internal firmware notification when an external device reads a characteristic?

TCdeveloper — Tue, 25 Aug 2020 20:21:27 GMT

I think Richard D.'s response was on the right track, although one doesn't have to provide any value.

I also think this link was helpful too: https://devzone.nordicsemi.com/f/nordic-q-a/9505/how-do-i-add-authorization-on-read-write-on-a-service-s-characteristics/35090#35090

Code that worked for me was:

ble_gatts_rw_authorize_reply_params_t auth_reply;

memset(&auth_reply, 0, sizeof(auth_reply));

auth_reply.type = BLE_GATTS_AUTHORIZE_TYPE_READ;

auth_reply.params.write.gatt_status = BLE_GATT_STATUS_SUCCESS;

And then in the BLE event handler, add a case that looks like:

case BLE_GATTS_EVT_RW_AUTHORIZE_REQUEST:

sd_ble_gatts_rw_authorize_reply(m_conn_handle, &auth_reply); // Generic reply to allow read.

// Do anything else you want here. Strobe an LED etc...

break;

RE: How does one get an internal firmware notification when an external device reads a characteristic?

Richard D. — Wed, 19 Aug 2020 23:54:16 GMT

One of the parameters to sd_ble_gatts_characteristic_add() is the attribute metadata, ble_gatts_attr_md_t. Set the element .rd_auth = 1.

Then in your ble event handler (depends on sdk version), add a case for BLE_GATTS_EVT_RW_AUTHORIZE_REQUEST. In that case, check the request for BLE_GATTS_AUTHORIZE_TYPE_READ. If so, you've got a read request for the indicated characteristic.

Note that this is not just a notification, you will need to provide the value that is being read rather than the gatts subsystem managing that for you.

I didn't find an example that shows it clearly, but the above should get you started.

Richard