topic Re: How to make changed UUIDs to take effect ? in Wireless MCU

How to make changed UUIDs to take effect ?

chandramohanc — Sat, 24 Sep 2016 13:50:54 GMT

I am trying to change UUIDs in gatt_uuid128.h, but after changing no matter how many times i compile, i see the old UUIDs always when i discover services and characteristics using my mobile app, please explain am i missing something

FYI:

I am using the given bluetooth_wireless_uart_demo example code

I did not change anything other than the UUIDs

I am using IAR compiler

Hardware FRDM-KW40Z

Before :

UUID128(uuid_service_wireless_uart, 0xE0, 0x1C, 0x4B, 0x5E, 0x1E, 0xEB, 0xA1, 0x5C, 0xEE, 0xF4, 0x5E, 0xBA, 0x00, 0x01, 0xFF, 0x01)
UUID128(uuid_uart_stream, 0xE0, 0x1C, 0x4B, 0x5E, 0x1E, 0xEB, 0xA1, 0x5C, 0xEE, 0xF4, 0x5E, 0xBA, 0x01, 0x01, 0xFF, 0x01)

After:

UUID128(uuid_service_wireless_uart, 0xba, 0x1C, 0x4B, 0x5E, 0x1E, 0xEB, 0xA1, 0x5C, 0xEE, 0xF4, 0x5E, 0xBA, 0x00, 0x01, 0xFF, 0x01)
UUID128(uuid_uart_stream, 0xab, 0x1C, 0x4B, 0x5E, 0x1E, 0xEB, 0xA1, 0x5C, 0xEE, 0xF4, 0x5E, 0xBA, 0x01, 0x01, 0xFF, 0x01)

Re: How to make changed UUIDs to take effect ?

santiago_lopez — Mon, 07 Nov 2016 18:07:30 GMT

Hi Chandra,

Sometimes smartphone applications store the last values from the device discovery procedure. It takes some connections for these applications to update that information. I implemented the changes you mention and tried to read the UUIDS using a Motorola G. After 3 or 4 connections (without changing the FRDM-KW40 firmware) the information in the application was updated.

If you can´t see the change, please try with another smartphone or application.

Best Regards

Santiago Lopez - Systems Engineer

Re: How to make changed UUIDs to take effect ?

b_manojkumar521 — Sat, 11 Apr 2020 05:26:33 GMT

Hi Santiago

Can you explain me how to give/change the name for profiles

I'm trying to give the name instead of unknown service and unknown characteristic

If you know the concept please explain to me, sir

Thanks in advance .!

Re: How to make changed UUIDs to take effect ?

santiago_lopez — Thu, 16 Apr 2020 19:38:15 GMT

Hi Manoj,

Showing the name of the attributes in the smartphone application depends on the smartphone having the correlation list between the UUID and the attribute name. When the client retrieves the GATT database information from the server, it will not share service, characteristic or attribute names but UUIDs. Each UUID is tied to a specific service, characteristic or attribute, some of them defined by BLE org and some others custom (like the Wireless UART in our example)

The ones defined by the BLE org, like 0x180D for Heart Rate Service, will be already defined in the smartphone application UUID database, and once it sees the known UUID, it will report the right attribute name. For custom UUIDs, it is less likely to have the real name in the UUID database and it will report Unknown UUID.

Here is a list of the BLE registered UUIDs https://www.bluetooth.com/specifications/gatt/services/

Saludos

Re: How to make changed UUIDs to take effect ?

b_manojkumar521 — Mon, 20 Apr 2020 20:36:35 GMT

I have another issue that,

1. How to send data from client to server

2. And with that data, I need to toggle an led

Save me with giving your valuable answer

Thanks in advance .! Sir .!