nRF5340 Zephyr OS board configuration - ram and flash sizes

[RAlexeev]

Why ram and flash size in a board configuration in Zephyr OS for nRF5340PDK doesn't match with declared on your site? According to your product specification, application processor of nRF5340 has 1 MB Flash and 512 KB RAM, network processor of nRF5340 has 256 KB Flash and 64 KB RAM. But you can see other values that in the board specification:

github.com/.../nrf5340pdk_nrf5340_cpuapp.yaml
ram: 64
flash: 256

github.com/.../nrf5340pdk_nrf5340_cpuappns.yaml
ram: 384
flash: 256

github.com/.../nrf5340pdk_nrf5340_cpunet.yaml
ram: 64
flash: 256

But in the case of nRF52840 ram and flash sizes in github.com/.../nrf52840dk_nrf52840.yaml match a product specification completely.

What is the reason for such the difference in the case of nRF5340?

[haakonsh]

It's a bit weird that they're not set to 512 each, but it is only a template, you'll have to create your own board definitions where your set the flash sizes of the secure and non-secure images according to your specific application's needs. 

[RAlexeev]

Thanks for your answer. Thus, all the time when I used this default template for my applications for nRF5340 PDK then they didn't see and use the whole RAM and Flash, did they?

[haakonsh]

That's true. Though I believe the  "missing" 64kB of RAM is reserved for something else. 

[RAlexeev]

Thank you! I wish I will get to know about this something else once ;-)