Bluetooth: Characteristic Value Showing up as N/A on nRF Connect App

RE: Bluetooth: Characteristic Value Showing up as N/A on nRF Connect App

Susheel Nuguru — Wed, 25 Sep 2024 14:30:38 GMT

When I tested this a month ago, the attribute value was changing for the one for which you were sending notification. After implementing the read function, the read in the app was also working fine.

Please note that reading in app and getting notified are two different things. If the read is not working correct, then I guess something with read function is not correct.

RE: Bluetooth: Characteristic Value Showing up as N/A on nRF Connect App

SarikaK — Tue, 24 Sep 2024 02:47:31 GMT

So I was able to see that notifications were enabled, but I could only read the value 00 for the attribute in the nRF Connect app. I am passing this function varying sine_value values from an array, so I was expecting to see the attribute value change accordingly in the app.

Not sure what else needs to be modified here—does attr_count need to be assigned a value?

RE: Bluetooth: Characteristic Value Showing up as N/A on nRF Connect App

SarikaK — Tue, 20 Aug 2024 20:27:07 GMT

Thanks, Susheel! I'll try this out and get back to you.

RE: Bluetooth: Characteristic Value Showing up as N/A on nRF Connect App

Susheel Nuguru — Thu, 15 Aug 2024 15:03:34 GMT

Just realized that you have not implemented the gatt read function for reading the attribute. Please fix your service definition as below

static ssize_t read_nfc_feature(struct bt_conn *conn,
				const struct bt_gatt_attr *attr, void *buf,
				uint16_t len, uint16_t offset)
{
	return bt_gatt_attr_read(conn, attr, buf, len, offset, NULL, 0);
}

/* Sine Wave Service Declaration */
BT_GATT_SERVICE_DEFINE(afe_svc,
	BT_GATT_PRIMARY_SERVICE(BT_UUID_AFE_DATA),
	BT_GATT_CHARACTERISTIC(BT_UUID_SINE_WAVE,
				BT_GATT_CHRC_READ | BT_GATT_CHRC_NOTIFY,
				BT_GATT_PERM_READ, read_nfc_feature, NULL,
				NULL),
	BT_GATT_CCC(afe_ccc_cfg_changed,
			 AFE_GATT_PERM_DEFAULT),
);

This should allow your app to read the attribute from nrf connect app.

RE: Bluetooth: Characteristic Value Showing up as N/A on nRF Connect App

Susheel Nuguru — Thu, 15 Aug 2024 12:48:34 GMT

sorry for testing this a bit late Sarika,

~~I see no issues with the read permissions testing this on iPhone14 with nRF connect for mobile app.~~

scratch that ..I am able to reproduce that it is not able to read the characteristic when pressing the down arrow. I will look into it and see if it is missing any permissions.

RE: Bluetooth: Characteristic Value Showing up as N/A on nRF Connect App

Susheel Nuguru — Wed, 14 Aug 2024 12:10:11 GMT

I am sorry Sarika, Did not reproduce the issue yet,

I will spend time tomorrow to reproduce this and if I manage to reproduce it, it will be easy to give a workaround/fix.

RE: Bluetooth: Characteristic Value Showing up as N/A on nRF Connect App

SarikaK — Tue, 13 Aug 2024 18:02:14 GMT

Just wanted to follow up on this!

RE: Bluetooth: Characteristic Value Showing up as N/A on nRF Connect App

SarikaK — Thu, 08 Aug 2024 23:11:52 GMT

devzone.nordicsemi.com/.../peripheral_5F00_nfc_5F00_pairing.zip

Thank you!

RE: Bluetooth: Characteristic Value Showing up as N/A on nRF Connect App

Susheel Nuguru — Thu, 08 Aug 2024 09:55:00 GMT

Seems right to have Read and Write permissions on this. Can you give give me your project to test for me to reproduce this on my desk? I will have to test this on Monday if you attach your project here.

RE: Bluetooth: Characteristic Value Showing up as N/A on nRF Connect App

SarikaK — Tue, 06 Aug 2024 22:56:53 GMT

My understanding is that AFE_GATT_PERM_DEFAULT should set the default GATT permissions for both read and write:

RE: Bluetooth: Characteristic Value Showing up as N/A on nRF Connect App

Susheel Nuguru — Mon, 05 Aug 2024 10:30:01 GMT

What is AFE_GATT_PERM_DEFAULT? are you sure if there are read permissions there?