NCS startup time is too long, reaching 1684ms

[Quay]

Hello everyone,

I've noticed that when using MCUBoot+External Flash+OpenThread+FOTA over BLE+PWM, the program startup time is extremely long, reaching 1684 milliseconds. As shown in the figure:D0 is VCC, and D1 is the main function executing PWM.

SDK+Toolchain：NCS v3.0.0

Board target：nrf52840dk/nrf52840

I have provided the source code of the project in the attachment, please check it out.5100.peripheral_lbs.zip

My goal is to reduce the startup time to less than 100ms, is it achievable?

[Håkon Alseth]

Hi,

 

Have you tried to disable SERIAL in all images, including mcuboot, and then check the boot-up time?

 

You can also try to switch the 32kHz clock source to internal RC:

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

 

Kind regards,

Håkon

[Quay]

Hi Håkon,

Thank you for your prompt reply.I added in both prj.conf and mcuboot.conf

CONFIG_LOG=n
CONFIG_SERIAL=n
CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y
CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n
CONFIG_CLOCK_CONTROL_NRF_K32SRC_250PPM=y

The startup time has been reduced to 1195 milliseconds, but it's still far from my target of 100 milliseconds.

[Håkon Alseth]

Hi,

 

Yes, I also still see a significant delay.

Could you disable the CC3xx in addition?

Here's how to set that up:  RE: High Current 400ms+ Startup Delay BLE Beacon Using RC Oscillator 

 

Note that you need this in both prj.conf and mcuboot.conf.

I got it down to 140 ms from cold-boot:

 

Kind regards,

Håkon

[Quay]

Hi Håkon,

Yes, after setting up prj.conf and mcuboot.conf, I observed the time reduced to 745ms.

# disable CC3XX
CONFIG_HW_CC3XX=n
CONFIG_ENTROPY_CC3XX=n
CONFIG_ENTROPY_NRF5_RNG=y
CONFIG_CC3XX_BACKEND=n

How did you achieve 140ms? Is there any other configuration I haven't set?

regards,

[Håkon Alseth]

Hi,

 

Try unsetting SB_CONFIG_BOOT_SIGNATURE_TYPE_NONE in sysbuild.conf.

 

Kind regards,

Håkon

[Quay]

Hi Håkon,

Yes,unsetting SB_CONFIG_BOOT_SIGNATURE_TYPE_NONE indeed reduced the time to 135ms, which is quite significant. However, this prevents the firmware from being verified, potentially leading to irreversible actions. Is it possible to implement verification only during the first firmware transfer after an OTA update?

regards