RE: GPIOs are not reset after DFU

bjorn-spockeli — Fri, 21 Apr 2017 11:47:58 GMT

Hi Kyle,

this is the expected behavior since the bootloader branches to the application, i.e. does not reset into the application.

The nRF52 will always will pass execution to the bootloader if it is present, which in turn will pass execution to the application, if it is valid. The bootloader will trigger one or several soft-resets during the DFU process, depending on the image type, but the final switch from bootloader to app is a branch operation.

This means that all configurations of peripherals if you've initialized in the bootloader, e.g. the GPIO peripheral, will persist through the branch operation. So the best practice is to have to un-initalize or reset the configuration to its default values the peripherals before the branch operation.

Best regards

Bjørn