DATA FILE TRANSFER FROM SD CARD TO MOBILE USING USB PROTOCOL. HOW TO DO IT IN NRF52840

[jagannathan GOPALAKRISHNAN]

we are using NRF52840 , with a SD card.  Data is stored in SD card in Text file or .csv file every 10 mins.  We want to push the data to Mobile App either using the BLE or using the USB protocol.  Kindly advice .

[Samiulhaq]

Hi Jorgen, thank you for the reply.

Yes, I understand that. You can't send more than a specific amount of bytes in one go using ble_uart. I have two questions:

1) Is there another possible way to send a file to the mobile app other than the ble_Uart?

2) What is the minimum time through which I can send a 234MB file to the mobile App?

I have read this blog in which they claim "The throughput measured may vary depending on the environment, but the maximum throughput should be around 1365 Kbps for BLE 5 High Speed, 775 Kbps for BLE 4.2, 128 Kbps for BLE 4.1 and 21.3 Kbps for BLE 5 Long Range. Be aware that there may be some inaccuracies in the measurements". How can I achieve this much throughput?

[Jørgen Holmefjord]

Please post your questions in a new ticket, as this is not related to the topic of this thread. Your questions relates to general BLE throughput and BLE services, which are already discussed in multiple threads. Please search other threads before posting your questions.

[Samiulhaq]

Thank you for the replay,

My question is exactly the same( reading file from SD card and sending to Mobile App) the only difference is file size which is 240MB in my case and nothing else. I have read almost all related threads but no one help me.

Till now I am able to read 220kb of data from the file in the SD card (the actual size of the file is 240MB) and send it to the mobile app(using the above example you have provided, with some modifications) and it is taking about 4 seconds to send 220kb of data. I want to reduce the time taken for the data to send to the Mobile app, I have applied all the suggestions in multiple threads but can't reduce the time to send the data to the mobile app. 

Any help will be highly appreciated. 

Kind Regards, 

Sami

[Jørgen Holmefjord]

I see you have already created a new ticket here:  Sending a complete file at once from SD card to Mobile App using NRF52840. 

Please continue the discussion in that thread.

[Samiulhaq]

Thank you for the reply,

I have created the thread but I can't get helped properly. I have applied all the suggestions but can't reduce my data transfer time. 

Regards,

Sami