C# PC app development with nRF52840-dongle

[Moshe Baker]

Our purpose is to integrate BLE 5 in our embedded application, and do it quickly.. We basically need to send/receive data with maximum throughput. 

Per thread below, we are planning to use the ble_app_uart on the embedded side.

For developing the PC app side, assume we are using the nRF52840-dongle you recommended in thread below, where can I find a code example in C# for doing this, implementing the NUS profile? I see there is JS/Node.js code of nrf-connect, but this is somewhat distant from our .NET environment.

Also i see in the Android app - nRF Toolbox - there is a UART app. So basically I'm looking for an equivalent C#/Windows code sample.

Does the pc-ble-driver in C++ cover the NUS service?

Spun off from:

Getting started with MBN52832 BLE Module

[Moshe Baker]

Another clarification - Could using pc-ble-driver-js provide better throughput performance than using the pc-ble-driver C++? Is the JS a layer above pc-ble-driver or a different implementation? 

[Einar Thorsrud]

Hi,

Sorry for the late reply.

Yes, since you are implementing the central, this will be used, and the connection interval is 6 * 1.25 ms = 7.5 ms. But as discussed earlier this is not the only thing that defines the throughput, you also need a large ATT MTU and large link-layer packets (using DLE). These are the result of negotiations.

[Einar Thorsrud]

Hi,

The pc-ble-driver-js is a layer on top of the pc-ble-driver, so you will not get better performance using that.

[Moshe Baker]

Thanks. I am receiving data packets of 244 bytes, which is the maximum as I understand. What else? I'm still at 80Kbps...

Also, can you point me to a PC NUS implementation I can use over API v5? I found some references, but still cannot get the correct descriptor UUID of 0x2902 for setting CCCD, I get 0x2803. This is my current PC log:

Serial port used: COM11
Baud rate used: 1000000
Info: Successfully opened COM11. Baud rate: 1000000. Flow control: none. Parity: none.
Status: 6, message: Target Reset performed
Status: 7, message: Connection active
Scan started
Received advertisement report with device address: 0xCB5E527FE36A
Connection established
Discovering primary services
Received an un-handled event with ID: 35
Received service discovery response
Discovering characteristics
Received characteristic discovery response, characteristics count: 2
Characteristic handle: 0x000C, UUID: 0x0002
Characteristic handle: 0x000E, UUID: 0x0003
Discovering characteristic's descriptors
Received descriptor discovery response, descriptor count: 1
Descriptor handle: 0x000E, UUID: 0x2803

[Einar Thorsrud]

Hi,

Moshe Baker said:

I am receiving data packets of 244 bytes, which is the maximum as I understand. What else? I'm still at 80Kbps...

There is nothing other to do than what we have discussed. Can you make a sniffer trace so that we can see what is actually happening on the link? That would make it easier to know in which direction to look further.

Moshe Baker said:

Also, can you point me to a PC NUS implementation I can use over API v5?

I don't have any PC side implementations, but the SoftDevice API is essentially the same regardless of using it directly or via the pc-ble-driver, so you could just refer to the SDK implementation. For version 5 API you could refer to <SDK 14.2>\components\ble\ble_services\ble_nus\ for the server implementation and <SDK 14.2>\\components\ble\ble_services\ble_nus_c\ client implementation, depending on which you need.

Moshe Baker said:

I found some references, but still cannot get the correct descriptor UUID of 0x2902 for setting CCCD, I get 0x2803.

Is this all of the log? As you know, 0x2803 is the assigned UUID for a characteristic declaration, and 0x2902 is for descriptor declaration. I would expect to see CCCD descriptors, so either there is an issue with your service discovery code or with the NUS server you are communicating with.