Reset into USB bootloader

RE: Reset into USB bootloader

Ken A — Tue, 12 Nov 2019 16:17:29 GMT

The watchdog logic still does not work.

In the main application, the default watchdog timeout is 2000 ms.

To reset into bootloader mode, I call:

nrf_wdt_reload_value_set((60000U* 32768U));
nrf_drv_wdt_channel_feed(wdtId);

#define BOOTLOADER_DFU_START 0xB1
sd_power_gpregret_set(0, BOOTLOADER_DFU_START);
NVIC_SystemReset();

In the bootloader, I call:

// set a long timeout
nrf_wdt_reload_value_set((60000U * 32768U));
nrf_wdt_reload_request_set(0);

ret_val = nrf_bootloader_init(dfu_observer);
APP_ERROR_CHECK(ret_val);

The bootloader still resets into the application after 2 seconds.

What could I be missing here?

RE: Reset into USB bootloader

Ken A — Mon, 26 Aug 2019 14:05:49 GMT

Never mind ... I realize now that the watchdog is still enabled through a soft reset. I added watchdog code to the bootloader application and now it stays in bootloader mode.

RE: Reset into USB bootloader

Ken A — Fri, 23 Aug 2019 16:26:04 GMT

I added code to the bootloader in main(), before calling nrf_bootloader_init(),

to blink LEDs in a certain pattern if

(nrf_power_gpregret_get() & BOOTLOADER_DFU_START) is true.

This proves that my application is setting BOOTLOADER_DFU_START correctly. However, the bootloader still jumps to the application.

Interestingly, if I add the line

nrf_power_gpregret_set(BOOTLOADER_DFU_START) before calling nrf_bootloader_init(), the bootloader always stays in bootloader mode on reset.

If it matters, I am using softdevice S140 for BLE functionality, and FSTORAGE_SD.

RE: Reset into USB bootloader

Vidar Berg — Fri, 23 Aug 2019 05:53:43 GMT

If it's possible to attach a debugger to your board I suggest that you open your bootloader project and place breakpoints in nrf_bootloader.c::dfu_enter_check() to find out why the NRF_BL_DFU_ENTER_METHOD_GPREGRET isn't returning true. I would also have checked if GPREGRET is set correctly.

RE: Reset into USB bootloader

Ken A — Thu, 22 Aug 2019 13:58:57 GMT

Vidar,

I followed your instructions, and it resets into the bootloader. The bootloader jumps immediately into the application. I want it to stay in the bootloader and wait for a firmware download even if t he application image is valid.

RE: Reset into USB bootloader

Vidar Berg — Wed, 21 Aug 2019 13:40:02 GMT

Hi,

The NRF_BL_DFU_ENTER_METHOD_GREPRET must be set to '1' in the bootloader's sdk_config.h file for this to work. Also, note that you can't access the POWER registers directly if you have the Softdevice enabled in your application, it will lead to a softdevice assertion. Use the SD API sd_power_gpregret_set() if it is enabled.

You may also consider using the DFU Trigger Library (USB). It's compatible with our existing DFU tools and is integrated into the connectivity example (\examples\connectivity\ble_connectivity\pca10059).