Peripheral Device Knowing Bluetooth Type of connection.

RE: Peripheral Device Knowing Bluetooth Type of connection.

Simon — Mon, 17 Feb 2020 12:33:08 GMT

I took a closer look at this and I think I know how to go about this.

In the peripheral, you can use the function sd_ble_gap_phy_update(..) after a connection is established, to update the speed to 2 Mbps. You will then get a response from the central whether the PHY is supported or not. If it is not supported you will receive the BLE event BLE_GAP_EVT_PHY_UPDATE with a status equal "Not Supported" (=BLE_HCI_UNSUPPORTED_REMOTE_FEATURE) and if it is supported you will receive this BLE event with status equal "Sucess" (=BLE_HCI_STATUS_CODE_SUCCESS). The Message Sequence Chart Peripheral PHY Update gives you a better overview of this.

The example examples\ble_central_and_peripheral\experimental\ble_app_att_mtu_throughput might be helpful to take a look at if you are going to implement this in your application.

Best regards,

Simon

RE: Peripheral Device Knowing Bluetooth Type of connection.

Farhouse — Mon, 10 Feb 2020 12:49:29 GMT

Thanks Simon for your anwnser.

May i ask another thing?

is there a flag or something inside the NRF52832 that would allow me to change the behaviour of my nrf device to make it run faster if the bluetooth connection its 5.0 instead of 4.2. As you explained, if the central device its a 4.2 connection, it wont use the 2Mbps bandwidth. Therefor, it doesnt make any sense to read the sensor at a higher speed, since it wont be using that bandwidth.

For example:

If the central device has only 4.2, the peripheral device will only read 25 times the sensor, and make a string that fixes in the 1Mbps bandwidth.

But if the central device uses 5.0, that means i have 2Mbps bandwidth and i could read the sensor 50 times.

Thats why im asking if there is a way for the peripheral device to know what type of connection the central stablished, and change the way it sends data to use that extra bandwidth. I know that if there isnt, i can just send a command over uart that means use the 2Mbps bandwidth.

thanks again for all the help and patience.

RE: Peripheral Device Knowing Bluetooth Type of connection.

Simon — Mon, 10 Feb 2020 11:48:10 GMT

Bluetooth 5 is backward compatible, which means that a BLE 5.0 device can connect to a BLE 4.2 device. Take a look at this and this case, which explains this in more detail.

"I don't know whether you are aware of it, but BLE 5.0 is backwards compatible, so you don't need to restrict yourself to a strict BLE 4.2 softdevice. All the features in 5.0 are optional, and you can chose to not support any of them. If you do support some of them, but want to communicate with a device that doesn't support that feature (a 4.2 device) then they will simply not use that feature."

Best regards,

Simon

RE: Peripheral Device Knowing Bluetooth Type of connection.

Farhouse — Fri, 31 Jan 2020 14:02:56 GMT

I would try to explain better.

The NRF52832 can work in bluetooth 4.2 and Bluetooth 5.0. meaning that it can work at 1Mbs or 2Mbs. for better compatibility with android devices im currently using 4.2 version, but i would like to allow devices that support 5.0 to use that version of bluetooth with my nrf52832 and also make my firmware transfer more data, as new speeds are available in the 5.0 version.

is there a simple way to do it? or i need to do it in a "propietary" way. (example: my own app sends me a data saying that the device supports bluetooth 5 and switch to that version).

is it better now?

RE: Peripheral Device Knowing Bluetooth Type of connection.

Simon — Fri, 31 Jan 2020 13:27:05 GMT

I'm not sure if I understand what you are asking about? Could you be more specific?

A BLE central device scans for advertisements from a peripheral device and establishes a connection through GATT. Check out our BLE tutorials for a deeper understanding:

Best regards,

Simon