Why the program can switch to bootloader from app sleep mode?

[oplinux]

Hi guys.

I flashed a uart-dfu Bootloader(SDK-location\nRF5_SDK_15.0.0_a53641a\nRF5_SDK_15.0.0_a53641a\examples\dfu\secure_bootloader\pca10056_uart), when the program run in APP(ble_app_uart) enviroment, I pressed button 1 made the app enter sleep mode, then I pressed button 4, the program run in bootloader dfu mode right away.

Why the program can switch to bootloader from sleep mode? I can't find the function code in ble_app_uart. Could you give me some advices. thank you very much.

[Vidar Berg]

Hi,

The bootloader starts before the application on startup (e.g. after a wakeup from System OFF reset - see my answer in your other post here), and it detects that button 4 is pressed.