DFU for nRF52840 Dongle that is not huge

[brianreinhold]

I need to install a BTLE application on an nRF52840 dongle that is enclosed in a case and therefore I do not have access to the reset button.

I have looked at some of the DFU examples in the SDK across various transports. I think the only possibilities for the dongle are the BLE and USB options. I am not really clear on how to use it and it appears there is already an nRF Connect application loaded onto these dongles.

The downside I see with these DFU projects is that they are HUGE! Much larger than my application. My application contains a cycle power and heart rate service and it searches for unconnectable advertisements with cycle and heart rate data, converts it to the cycle power and heart rate standards and events this data to a connected client. It uses SoftDevice S140.

However the application size is less than half the size of DFU. Why is the DFU so inefficient? Its using far less BTLE than my application.

Given that, I would also like to know if I can use these DFU applications on the dongle and how to I get them there. I looked at the USB trigger but the size of that was absolutely absurd, it was 7 times the size of my application.

All this to skip having to push the little reset button....

[Vidar Berg]

I need to install a BTLE application on an nRF52840 dongle that is enclosed in a case and therefore I do not have access to the reset button.

Is this the Nordic "pca10059" dongle?

I have looked at some of the DFU examples in the SDK across various transports. I think the only possibilities for the dongle are the BLE and USB options. I am not really clear on how to use it and it appears there is already an nRF Connect application loaded onto these dongles.

The Nordic dongles come pre-programmed with the Open Bootloader with DFU to allow DFU of the application and Softdevice over the USB interface. Einar covers this in more detail in the tutorial here: https://devzone.nordicsemi.com/nordic/short-range-guides/b/getting-started/posts/nrf52840-dongle-programming-tutorial

The downside I see with these DFU projects is that they are HUGE! Much larger than my application. My application contains a cycle power and heart rate service and it searches for unconnectable advertisements with cycle and heart rate data, converts it to the cycle power and heart rate standards and events this data to a connected client. It uses SoftDevice S140.

But does your app include the  USB stack? The bootloader would also have been considerably smaller if it had not include the crypto libraries for FW validation.

Given that, I would also like to know if I can use these DFU applications on the dongle and how to I get them there. I looked at the USB trigger but the size of that was absolutely absurd, it was 7 times the size of my application.

It do not see how it could be 7x bigger. I would expect it to add less than  20kb. Was this the library you attempted to integrate: DFU Trigger Library (USB)?