nRF9160 SRAM Partition changes

RE: nRF9160 SRAM Partition changes

Martin Lesund — Mon, 13 May 2019 08:07:38 GMT

Please see the updated answer to that thread.

RE: nRF9160 SRAM Partition changes

Martin — Sat, 11 May 2019 01:01:08 GMT

I stronly would suggest that Nordic builds/releases another bsd library that only uses 8k or 16k of memory.
Following the sugested SAM partition of 64kb secure, 64kbkb bsd that leaves you only 128kb for the application.

For example: I am porting an appliction that used to access an ublox cellular modem and uses at most 2kb of RAM. Why should I waste the other 62kb of RAM?

The secure memory can easily be reclaimed but not the BSD memory.

And I think it implies from the original question that JL just wanted to increase the available memory for the non-secure application.

RE: nRF9160 SRAM Partition changes

gonzalezjl — Tue, 07 May 2019 12:57:08 GMT

Hi Martin,

Is it possible then to have discontiguous Non-Secure areas in SRAM to be used by the application?

&sram0 {

reg = <0x20000000 DT_SIZE_K(8)>;

};

&sram0_ns {

reg = <0x20002000 DT_SIZE_K(56)>;

};

&sram0_bsd {

reg = <0x20010000 DT_SIZE_K(64)>;

};

&sram1_ns {

reg = <0x20020000 DT_SIZE_K(128)>;

};

Thanks,

RE: nRF9160 SRAM Partition changes

Martin Lesund — Tue, 07 May 2019 07:13:55 GMT

Hi JL,

Update 20.01.2020:

Check the updated BSDLIB documentation for the latest information.

"The secure domain memory is divided into segments of 8 KB RAM blocks. Because the size of the BSD library block is 0xC020 bytes, it is not aligned to full 8 KB blocks. It occupies six blocks and a small part of a seventh block.

The leftover memory in that seventh block (8160 bytes, starting at address 0x2001 c020) is configured as non-secure, but it can be used by the application."

Old answer:
The BSD Library has an absolute position and is fixed at starting address 64K and size of 64K (0x20010000 – 0x2001FFFF).

This cannot be moved.

However, all other partitions might be moved.

Note: The BSD memory always has to be Non-Secure configured.

You can find the "Default flash planning" in the file: [/ncs/zephyr/boards/arm/nrf9160_pca10090/nrf9160_pca10090_partition_conf.dts]

There it's also documented that "64 kB SRAM reserved for and used by the BSD socket library."

Best regards,
Martin L.

RE: nRF9160 SRAM Partition changes

Martin — Tue, 23 Apr 2019 12:06:16 GMT

Me too.
I have a similar (more general) question still open till today about this.

devzone.nordicsemi.com/.../nrf9160-software-architecture-boot-bsd-app-and-partitioning