ios nrf loader timeout during upload

[Frank Zhao]

I have the nRF Loader app installed on an iPad Mini. I have the dfu_dual_bank_ble firmware from SDK V5.0.0 and SoftDevice V6.0.0.1-beta loaded on my nRF51822.

The app is able to see the device named "DfuTarg" and pair with it, the status becomes "ready", but when it tries to upload, it will hang for a minute and then report an unexpected timeout error.

The LED that indicates connection establishment is on when DfuTarg is selected, but it goes off when the timeout error arrives.

How do I make DFU work? What is causing the timeout?

[Ole Morten]

You can change how many packets the iOS app sends between receiving a confirmation, which may help NO_MEMORY issues, by tuning the setting of the notificationPacketInterval in setFirmwareURL of the DFUController.

The algorithm to set this number was chosen based on getting a reasonable amount of updates over an application upload, but doesn't check the size it ends up at. May I ask how large the binary you're trying to upload is? It could be that this number simply becomes too big for the buffers on the nRF51822 side if the binary itself is big.

[Frank Zhao]

I am just trying out ble_app_rscs, 17260 bytes

changing notificationPacketInterval to 1 worked! it seems to transfer 20 (which is max packet size) bytes per notification now.

should I just increase it until it stops working?

Also although it seems to detect a valid application because it attempts to launch it, the application itself seems to be self-resetting... How do I go about generating a .bin file from my own .hex file?

I realize the above question is actually very simple to answer myself, but hex files specify addresses, bin files do not, I need to know the proper way of doing the conversion because of the address offset.

[Ole Morten]

That's interesting indeed. I saw NO_MEMORY errors once in a while when developing the app, but that was only when having long printf-s several places in the bootloader. I would not at all expect it to happen with the bootloader directly from the SDK. Do you still see errors when not doing any debug output?

There isn't any magic about creating a bin file to be used with nRF Loader, you can for example do like this to do such conversion: https://devzone.nordicsemi.com/index.php/how-to-use-the-nrf-loader-to-do-ota#reply-3155

[Frank Zhao]

I was compiling using MicroLib, because the original project configuration did not seem to fit, it threw a bunch of linker errors that were similar to some previous not-enough-RAM problems I faced. Enabling MicroLib allowed the project to compile, but I suspect it made it run slower.

I just tested bootloading my own application and it works. I added the command

fromelf --bin --output "[email protected]" "#L"

to my post build execution steps to generate the bin

[Ole Morten]

I believe that the bootloader should compile out of the box, but I suspect that disabling optimizations might make it not fit anymore. Anyway, great that you've gotten further!