increase and know the max data possible to send

[lm]

Hello, i'm using the example ble app uart and I would like to know the maximum data that I cand send to my putty and my phone. Could I have to procedure? I would like to send a lot of data 

Thank you in advance

[Karl Ylvisaker]

Hello,

To increase your throughput you will need to modify your connection parameters.
Please see the throughput documentation for the SoftDevice you are using for details about which parameters you should use for maximum throughput.

Best regards,
Karl

[lm]

Hello Karl, i saw this document but i'm going to explain to you my goal : send unlimited data/informations (maybe 100k of data) how can i do this? because for now I have a limit of 244 bytes/data and it is not useful for me. Thank you in advance 

[Karl Ylvisaker]

Oh, my mistake - in my previous comment I recommended that you make use of the pc-ble-driver for your application development, but the issue here is actually on the phone's side.
Do I understand you correctly that the 244 bytes you are sending correctly arrives at the PC's serial terminal, as expected?
So, the only issue is queueing more data than 244 bytes for sending on the phone's side?

What I wrote in my previous comment about the nRF Connect BLE application for desktop is also true for the nRF Connect for smartphone application. It is made primarily to make development and testing easier, so using it for large transfers is not ideal.

Best regards,
Karl

[lm]

no problem :) yes but i only issue is to create the fragments actually I saw this function that could help in the main.c but I don't know where to put it.

static void send_long_buffer(uint8_t *buf, uint16_t buf_length)
{
    uint32_t err_code;
    uint16_t length;
    uint32_t offset = 0;
    uint32_t max_payload_size = 244;

    // Exécutez cette boucle jusqu'à ce que le buffer entier soit transmis avec succès

    while(buf_length > 0)
    {
        //Envoyer un segment/paquet du buffer total
        do
        {
            length = (buf_length > max_payload_size) ? max_payload_size : buf_length;
            err_code = ble_nus_data_send(&m_nus, buf + offset, &length, m_conn_handle);
            if ((err_code != NRF_ERROR_INVALID_STATE) &&
                (err_code != NRF_ERROR_RESOURCES) &&
                (err_code != NRF_ERROR_NOT_FOUND))
            {
                APP_ERROR_CHECK(err_code);
            }
        } while (err_code == NRF_ERROR_RESOURCES);

        //Pour chaque téléchargement de paquet réussi, augmentez le décalage du buffer et réduisez la longueur de buffer restant

        offset += length;
        buf_length -= length;
    }
}

[lm]

I don't where to use this function or to call it thank you in advance

[lm]

And the 244 bytes can be transmitted but we have 245 bytes we have an error and nothing is transmitted.

[Karl Ylvisaker]

lm said:

yes but i only issue is to create the fragments actually I saw this function that could help in the main.c but I don't know where to put it.

Yes, but this is still all on the peripheral side - which is working as expected.
The function you shared is a peripheral side function, which will not affect how you are able to send things from the phone to the peripheral.
The changes you will need to make is on the central(phone) side, so that you are able to queue your large dataframe for transfer, or perhaps I am misunderstanding you again?

lm said:

And the 244 bytes can be transmitted but we have 245 bytes we have an error and nothing is transmitted.

True, this is as expected - when an error is returned it means that the function call as a whole failed, in which case nothing will be transmitted and you will have to re-do the function call.

Best regards,
Karl

[lm]

Okay, maybe we don't understand each other but my problem is : 

- from PHONE to my COMPUTER :

 data is not transmitted at 245 bytes and I have a gatt error. My goal is to create a function as I show you to fragment the code and send 2 notifications to my computer. 

I would like to know what I have to modify on the ble app uart code to create directly those fragments of 244 bytes each.

but from COMPUTER to PHONE I don't have any problems :)

[lm]

but my problem is that I'm new with dev and making chunk is not easy so I showed earlier my idea and I would like to have your opinion about this function and where I should put it thank you again

[Karl Ylvisaker]

lm said:

- from PHONE to my COMPUTER :

Yes, I think I understand your issue.

lm said:

my problem is that I'm new with dev and making chunk is not easy so I showed earlier my idea and I would like to have your opinion about this function and where I should put it thank you again

Yes, you showed me some code for the nRF device, however as I mentioned the issue is not with the nRF device itself - the BLE protocol has a maximum byte limit per packet, and thus you can not just change a configuration to allow larger packets.
Instead, you will need to work with this requirement on your phone's side, by fragmenting the message into pieces that does not exceed the BLE limit.

In essence; your nRF BLE UART device is working as intended, the issue is just that each message from your phone can not exceed the BLE packet limit, and so you must divide the message into chunks that fit into the BLE packet limit.
The nRF Connect application can not do this for you, unfortunately, so you will have to find a way to have this done - either by doing it manually yourself using the nRF Connect application (not feasible), or by creating an application on your phone that fragment and send data to your connected BLE UART device sequentially.

Best regards,
Karl

[lm]

Thank you so much for your help. :) 

[Karl Ylvisaker]

lm said:

Thank you so much for your help. :) 

No problem at all, I am happy to help you! :)

Please do not hesitate to open another ticket if you encounter any other issues or questions in the future.

Good luck with your development!

Best regards,
Karl