Add mcuboot to connect SDK BLE sample "central and peripheral"

[Andreas3T]

Hi,

I'm trying to add BLE DFU to the nrf connect SDK sample "central and peripheral" for the nRF52832

I've done the following:

Add configurations to proj.conf

# Enable mcumgr.
CONFIG_MCUMGR=y

# Enable most core commands.
CONFIG_MCUMGR_CMD_IMG_MGMT=y
CONFIG_MCUMGR_CMD_OS_MGMT=y

# Ensure an MCUboot-compatible binary is generated.
CONFIG_BOOTLOADER_MCUBOOT=y

# Allow for large Bluetooth data packets.
CONFIG_BT_L2CAP_TX_MTU=252
CONFIG_BT_BUF_ACL_RX_SIZE=256

# Enable the Bluetooth (unauthenticated) and shell mcumgr transports.
CONFIG_MCUMGR_SMP_BT=y
CONFIG_MCUMGR_SMP_BT_AUTHEN=n

# Some command handlers require a large stack.
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=4096

Created a directory child_image with an empty mcuboot.conf file

When I build it with the command:

west build -b nrf52dk_nrf52832 --pristine

I get the following error:

zephyr/zephyr_pre0.elf section `text' will not fit in region
FLASH' region `FLASH' overflowed by 27752 bytes

Looking at the resulting size with arm-none-eabi-size of the mcuboot zephyr.elf i get:
text  data bss   dec   hex  filename
33082 500  23545 57127 df27 zephyr.elf

And the sizes for the central and peripheral without mcuboot:
Memory region Used Size   Region Size  %age Used
FLASH:        248516 B    512 KB       47.40%

Is there some memory allocated for the DFU slot which causes the overflow?

Thanks in advance,
Best Regards, Andreas

[Hieu]

Hi Andreas,

Is there some memory allocated for the DFU slot which causes the overflow?

There will also be memory allocated for the MCUboot bootloader as well, it is the combination of those that give you that build failure.

If you run the memory report in a project where you can successfully build with DFU, like the Peripheral LBS, you can see the slots in the Partition Manager report.

To get more spaces, you could try to turn off all features unused. In the Peripheral UART sample, there is the prj_minimal.conf config file, where this is demonstrated.

I tried to borrow most of the configs from Peripheral UART over to Central and Peripheral HR and was able to build with MCUboot enabled. However, the ROM usage is still very high 95%. This is without any feature other than in the sample. Depends on your future plan, that number might be too high, and you might want to consider SoC variants with more flash.

Below is a screenshot of the Partition Manager report from my attempt for your reference.

Hieu

[Andreas3T]

Alright, thanks for the help!

[Andreas3T]

That's great! Thanks for the info :)

[variant]

Are there any implications for Bluetooth certification when using the Zephyr Bluetooth Controller?

[Hieu]

Thanks a lot variant for raising a good point. I should have included that in my reply.

cc. Andreas3T & markuckermann 

Nordic qualifies the Zephyr Host and the SoftDevice Controller, which you can use in the qualification process for your products. However, we don't qualify the Zephyr Controller, so projects that use it will have to get qualification for the Controller themselves.

As a reference, see the qualification documentation for the nRF52832.

This is a downside of using the Zephyr Controller. My apology for being unable to think of it. I was too focus on the technical aspect and missed non-technical details.

See also: Qualified Design IDs (QDIDs) and Declaration IDs (DIDs) – Bluetooth SIG Inc

[Hieu]

By the way, another disadvantage is that the Zephyr Controller is incompatible with the multi-protocol support in NCS.

I am not saying this to discourage anyone from using the Zephyr Controller. However, since I am around, and since I had said that it is a good idea to save size, I feel compelled to list all disadvantages I know of.

[Luca Nisti]

Thanks for useful information. I need couple of clarification:
1. CONFIG_BT_LL_SOFTDEVICE is not well documented, could you explain this feature what enable/disable

2. I run the code with the central_and_peripheral_hr example. When the CONFIG_BT_LL_SOFTDEVICE is disable the dk stop to work as central but carry on working good as peripheral. is there an exaplnation to that? thanks

[Hieu]

Hi Luca,

Luca Nisti said:

1. CONFIG_BT_LL_SOFTDEVICE is not well documented, could you explain this feature what enable/disable

Even though its documentation says only "Use SoftDevice Link Layer implementation," it would make more sense if you read this documentation page: 

Bluetooth LE Controller — nRF Connect SDK 2.3.0 documentation (nordicsemi.com)

Luca Nisti said:

2. I run the code with the central_and_peripheral_hr example. When the CONFIG_BT_LL_SOFTDEVICE is disable the dk stop to work as central but carry on working good as peripheral. is there an exaplnation to that? thanks

I am quite surprised it works at all. However, this is unrelated to the topic discussed here. Please open a new question for that.

[Luca Nisti]

Thanks, I fixed adding the following lines when using the Zephyr LE controller:
CONFIG_BT_HCI=y
CONFIG_BT_CTLR=y
CONFIG_BT_LL_SW_SPLIT=y