S130 DFU BLE Bootloader: no timeout?

[Mario Ribeiro]

Hello,

As far as I understand previous versions of DFU BLE bootloader implemented a timeout so if DFU is not being used and an app is present it will run after a few time.

I can't see anything on the latest SDK (12). Can't exit from DFU unless I send another update packet (.zip).

Any ideas on how to return to app code if present?

[bjorn-spockeli]

My suggestion would be to start the watchdog timer(WDT) once you enter nrf_dfu_init() in nrf_dfu.c and then feed it everytime the bootloader handles requests from the DFU controller. Configure and start the WDT by adding the following code snippet to nrf_dfu_init() after the if(enter_bootloader_mode != 0 || !nrf_dfu_app_is_valid()) statment

 //Configure WDT.
    NRF_WDT->CONFIG         = (WDT_CONFIG_SLEEP_Run << WDT_CONFIG_SLEEP_Pos);       // Configure WDT to run when CPU is asleep
    NRF_WDT->CRV            = 3932159;                                              // Timeout set to 120 seconds, timeout[s] = (CRV-1)/32768
    NRF_WDT->RREN           = WDT_RREN_RR0_Enabled << WDT_RREN_RR0_Pos;             // Enable the RR[0] reload register
    NRF_WDT->TASKS_START    = 1;                                                    // Start the WDT   

Then add the snippet below to the nrf_dfu_req_handler_on_req() function in dfu_req_handling.c

// Reload the WDTs RR[0] reload register
NRF_WDT->RR[0] = WDT_RR_RR_Reload; 

I have also attached the main.c and dfu_req_handling.c files below which include the snippets.

nrf_dfu.c

dfu_req_handling.c

Best regards

Bjørn

[Mario Ribeiro]

Great! I was already trying something like that using an "app_timer" which is overkill. WDF does the job wonderfuly. I also added an op code do Control Point characteristic so I can remotely reset the nRF51 while in DFU mode. Thanks!

[bjorn-spockeli]

Happy to help :)

[Dave_couling]

Why would Nordic remove the DFU Transfer Timeout (previously an app_timer) that was present in the previous Bootloaders? This should be a default supervisor timeout of the process to prevent erroneous power consumption. Also adding a WD is not trivial because it would need to be supported both in the Bootloader annd Application, as it persists over soft-resets.

[bjorn-spockeli]

@dave_couling : I agree that the bootloader should timeout if there is no "DFU Activity" to avoid excessive current consumption. My guess is that this was unintentionally left out when the bootloader was redesigned in the SDK v11.0.0/SKD v12.0.0 transition. I've reported this internally.