nRF5340 takes too long from Power ON to start executing the main application

[neo_here]

Hi, we have a custom nRF5340 based device. Has NISB and MCUBoot Enabled. It takes about 2.5 seconds to get into the application and BLE advertisement to start.

Wanted to know how do we go about narrowing down the cause and potential solutions.

We are on nRF Connect SDK 2.6.1

[neo_here]

I was able to find the Devzone case used by the HW team. 

devzone.nordicsemi.com/.../312445


Also, what would you suggest to investigate SW Delays, especially NISB and MCUBoot ? GPIO Toggle at different stages ? 

[Elfving]

neo_here said:

GPIO Toggle at different stages

Yes, try this.

neo_here said:

I was able to find the Devzone case used by the HW team. 

And your HW was not changed after this point?

Regards,

Elfving

[neo_here]

Yes, the HW hasn't changed after this point. 

[neo_here]

Elfving   Did some more experiments and I see this for time taken at each of the stages. NSIB starts executing immediately and seems like it's MCU boot which is taking quite a while to find the image and jump to the image. This is on our board with the production firmware. 

*** Booting NSIB v3.5.99-ncs1-1 ***
Attempting to boot slot 0.
Attempting to boot�*** Booting NSIB v3.5.99-ncs1-1 ***
Attempting to boot slot 0.
Attempting to boot from address 0x8000.
Verifying signature against key 0.
Hash: 0x40...26
<<<Above loads within 16ms of power ON>>>

Firmware signature verified.
Firmware version 1
�Booting (0x8000)
<< +150ms >>>

*** Booting mcuboot v3.5.99-ncs1-1 ***
I: 12 Sectors of 4096 bytes
I: alloc wra: 0, f40
I: data wra: 0, f4
I: qspi_encryption_config
I: qspi_encr_setup OK
I: Starting bootloader
I: Image index: 0, Swap type: none
I: Image index: 1, Swap type: none
<< +600ms >>

I: Bootloader chainload address offset: 0x28000
I: Jumping to the first image slot
<< +1100ms >>

[00:00:00.002,349] <dbg> qspi_nor: configure_chip: RDSR 40 QE 1 need 1: no-change
*** Booting application v3.5.99-ncs1-1 ***
[00:00:00.010,620] <inf> fs_nvs: 12 Sectors of 4096 bytes
[00:00:00.010,620] <inf> fs_nvs: alloc wra: 0, f40
[00:00:00.010,650] <inf> fs_nvs: data wra: 0, f4
[00:00:00.011,840] <inf> qspi_encr: qspi_encr_setup OK
<< +512ms >>

[neo_here]

I added some more timestamps in MCUBoot and seems like it spends more than a second just in mcuboot main()

uart:~$ *** Booting NSIB v3.5.99-ncs1-1 ***
Attempting to boot slot 0.
Attempting to boot from address 0x8000.
Verifying signature against key 0.
Hash: 0x40...26
Firmware signature verified.
Firmware version 1
�*** Booting mcuboot v3.5.99-ncs1-1 ***
I: 12 Sectors of 4096 bytes
I: alloc wra: 0, f58
I: data wra: 0, d0
I: qspi_encryption_config
I: qspi_encr_setup OK
I: Entering MCUBoot Main uptime -> 289
I: Starting bootloader
I: Image index: 0, Swap type: none
I: Image index: 1, Swap type: none
I: Bootloader chainload address offset: 0x28000
I: Jumping to the first image slot
�: Till Before do_boot  uptime -> 1429