Microbit development with Segger Embedded Studio & SDK 12.2

[brycheiniog]

All,

I recently acquired a BBC Microbit and have been having a play with trying to setup a development environment using the Segger Embedded Studio and the Nordic 12.2 SDK. I was wondering if anybody else had been down this road before me and had a working setup?

I have something that is almost working but falls over at some point during initialisation when running the ble beacon example. I have been able to successfully run the peripheral blinky example after modifying the LED mapping in the board config.

The high level steps I have followed so far are:

Firstly I flashed the LPC micro on the Microbit with the J-Link firmware as described here: www.segger.com/bbc-micro-bit.html

After this I am able to run the simple examples that Segger provide without any issues.

I then tried following this blog on using the Nordic SDK with Embedded Studio: devzone.nordicsemi.com/.../

I have used the above as a guide but changed targets and so on so that as far as I can tell I am building for the nrf51822 on the Microbit. I imported the ble_app_beacon_pca10028_s130 project as the basis for my experiments. I have the following segment placement macros defined: FLASH_START=0x1b000 SRAM_START=0x200013c8

This downloads without issue to the Microbit and I can step through the init code until it gets to the call to: ble_stack_init()->SOFTDEVICE_HANDLER_INIT()->sd_softdevice_enable()

After this it seems to get stuck and never returns. If I stop the core with the debugger it is normally around 0x91D0.

I haven't touched the settings in pca10028.h and I am wondering if it is something to do with the clock settings?

Any help would be appreciated :).

Jonathan

[Håkon Alseth]

Hi,

Getting stuck in softdevice_enable (ie: no error code return) is normally due to incorrect LFCLK source being used. I believe the microbit does not have an external 32k LFCLK, so you'll have to use the internal 32k RC oscillator instead. Here's how you configure that (in main.c::ble_stack_init()) devzone.nordicsemi.com/.../

Note: The microbit is a 256k flash and 16k RAM device, while the pca10028 is 256k/32k RAM, so you might have to adjust the RAM mapping for larger projects.

Cheers, Håkon

[brycheiniog]

Fantastic :). After changing the clock source as per your link, and then increasing the SRAM Start address (The soft device raised an error about insufficient RAM) it all burst into life!

Thanks for your help.

[Natael]

Hello,

I have been trying to use the microbit for a university project. I would like to program It with segger as I have done with the nrf58333.

However I dont have any reference about how yo do It.

Could you provide a basic example. I would aprecciate so much.

Besr regards :)

[Håkon Alseth]

Hi,

 

According to Segger's forum, this should be available on their website:

https://forum.segger.com/index.php/Thread/7707-SOLVED-j-link-for-BBC-micro-bit-v2/?postID=28740

 

Firmware and howto is available in the link in the replies in the above thread.

 

Kind regards,

Håkon

[Natael]

Hi,

The question is that there are not any documents about how to program It.

As you know, nRF52833 & microbit V2 has the same proccesor.

Do you know if the things done in the nRF52833 could be usted on the microbit?