Bootloader - serial output of logging info

RE: Bootloader - serial output of logging info

Amanda Hsieh — Mon, 02 Nov 2020 13:33:54 GMT

Hi Marie,

Sorry for the mistake. It is NRF_LOG_BACKEND_UART_ENABLED that should be enabled for log UART backend in the sdk_config.h. I have corrected the previous reply.

1) If you update via USB, please refer to the sdk_config.h under nRF5_SDK\examples\dfu\secure_bootloader\pca10040_usb_debug\config and enable NRF_LOG_BACKEND_UART_ENABLED. You could see the log with the terminal tool.

If you use pca10040_uart_debug, do not logging over UART. Instead, you should use RTT logging. The example bootloader projects come in pairs, one with debug logging over RTT and one without. Since you have used <SDK>\examples\dfu\secure_bootloader\pca10040_uart, I would like you to try <SDK>\examples\dfu\secure_bootloader\pca10040_uart_debug instead, and observe the logs using Segger RTT Viewer.

2) The bootloader start address is stored in one of the UICR register, which is written when you flash the bootloader to the nRF52832, see nrf_bootloader_info.c in the bootloader example. The MBR will check this UICR register on boot and then jump to the bootloader if there is an address present. On jumping to the application, the bootloader will jump to the SoftDevice, and then the SoftDevice will jump to its end address where it expects the application to be located. Also, see this post.

If your application runs without the softdevice, you should set the flash start address to 0x1000 (end of MBR) and set RAM_START to 0x20000008 for the MBR application. See this post.

With SoftDevice, the flash start address should be 0x0002 6000 (end of SoftDevice) for s132.

-Amanda H.

RE: Bootloader - serial output of logging info

MarieMaurer — Thu, 29 Oct 2020 14:09:09 GMT

Thanks for your answer!

1) I already have this define set to 1. But then I get

undefined reference to `nrf_log_default_backends_init'

More defines needed? Or modules I must add?

What about e.g. NRF_LOG_BACKEND_UART_ENABLED? But just tried, it makes at least no difference for this error.

What is difference between define prefixed with NRF_ and the ones without it? One for internal, one for user?

2) One is

FLASH (rx) : ORIGIN = 0x71000, LENGTH = 0xd000

the other is

FLASH (rx) : ORIGIN = 0x78000, LENGTH = 0x6000

This section is in flash. When it is once at this address, once at other address, how does caller know, where to call the bootloader? I assume MBR is started first via vector table, SP and IP. And then? What and how does MBR know how to continue?

RE: Bootloader - serial output of logging info

Amanda Hsieh — Thu, 29 Oct 2020 13:38:33 GMT

Hi Marie,

[quote user=""]1) What defines do I need to set to debug out of serial port?[/quote]

You can enable NRF_LOG_BACKEND_UART_ENABLED In the sdk_config.h of the example as

// <e> NRF_LOG_BACKEND_UART_ENABLED - nrf_log_backend_uart - Log UART backend
//==========================================================
#ifndef NRF_LOG_BACKEND_UART_ENABLED
#define NRF_LOG_BACKEND_UART_ENABLED 1
#endif

Then, you should be able to see the debug log in the serial terminal. See the Logger module documentation.

[quote user=""]Can you give me a few hints about side effects of this change?[/quote]

As long as you have enough space for the application and bootloader, I think that should be fine. In the secure_bootloader for uart example, you might find the bootloader address is different from the Memory layout documentation.

-Amanda H.