NRF9160 Persist Ram

[Thomas]

Hi,

I am trying to set up a region of RAM to store variables that persist across soft reboots but am unsure how to do it in this environment. I would normally define a region of RAM in the linker script, and store uninitialised variables in it. How do I do that in the zephyr environment for the NRF9160?

Kind regards,

Thomas

[Øyvind]

Hello Thomas, 

Just did a quick test here in the Hello World sample, and you should be able to do what you are asking.

Fullscreen main.c Download

/*
 * Copyright (c) 2012-2014 Wind River Systems, Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr.h>
#include <sys/printk.h>
#include <power/reboot.h>

u8_t test_array[0x400] __attribute__((section(".noinit")));

void main(void)
{
	printk("%u\n", test_array[0]);
	printk("Hello World! %s\n", CONFIG_BOARD);

	test_array[0]++;

	k_sleep(K_SECONDS(1));
	sys_reboot(0);
}

And in the prj.conf add the following:

CONFIG_REBOOT=y

This will count one and reboot, count one, and reboot. 

Let me know how that works for your application. 

Kind regards,
Øyvind

[Thomas]

Thank you Øyvind,

How do you define a specific region in RAM for it though, like you would in a linker script? Is it the partition conf file that needs changing?

Kind regards,

Thomas

[Øyvind]

You don't. This is a dynamic range set automatically by the OS.

Kind regards,
Øyvind

[Thomas]

I figured it out, you can use zephyr_linker_sources() to add sections to the linker file.

Kind regards,

Thomas