Broken images from nrf52-ble-image-transfer-demo

[Kirak]

I have built a BLE image transfer demo between iPhone 15 and nrf52840 using the following two code:

https://github.com/NordicPlayground/nrf52-ble-image-transfer-demo

https://github.com/NordicPlayground/iOS-Image-Transfer-Demo/tree/master?tab=readme-ov-file

While the iPhone app works, I found it shows broken images most of the time, especially when I use higher resolution, see below. Has anyone seen this issue with Android or iPhone? 

I put the camera module on nrf52840 using side connection, simply wired the third pin into 5V of the other end following this: https://github.com/NordicPlayground/nrf52-ble-image-transfer-demo?tab=readme-ov-file#nrf52840-using-side-connector

Any suggestion on how to debug / fix this would be helpful, thanks!

[Kirak]

I just checked CRC on both sides, and they are equal while images are still broken. My understanding is that writeWithoutResponse (write command not write request) may involve packet drops but in my case all packets arrive with correct CRC (i.e., correct order) so I suspect the image from NRF board itself is broken before transmission. Is there a way to debug image from the board, e.g., directly get image from board to laptop over USB?

[Hieu]

Hi Kirak,

In main.c of the BLE Image Transfer project, you will find the raw image data being used for sending here between line 856 and 871. You can debug the image data buffer being used there.

Hieu