Ble mesh: autoprovisioning and address selection

[stefanogradozzi]

After a lot of efforts I managed to autoprovision and autoconfigure my nrf52840 board and a series of nrf52840dongles (provisioning and configuring inside the software and not through external app).

In particular, I have configured a switch and a led like a client and his server in an element of my node.

I write the address of the nodes in a particular location of memory (as you can see from the code below)

All is OK: when I toggle the switch on nrf52840 board, the corresponding leds on dongles go on/off.

But if I make an erase/flash operation on the board and then I rewrite the same address in the same memory location, the board stops communicating with the other nodes.

I have to make another erase/flash operation and then write in memory another adderss.

How is this possible?

The code that I use for autoprovisioning is this:

#include "provision.h"
#include <zephyr/logging/log.h>

LOG_MODULE_DECLARE(main);

static const uint8_t net_key[16] = {
	0x6f, 0xea, 0x5b, 0x86, 0x38, 0x45, 0x26, 0xb9,
	0x0e, 0x7b, 0x73, 0x0c, 0x69, 0x94, 0x75, 0x0a,
};

static const uint8_t dev_key[16] = {
	0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0x01,
	0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0x01,
};

static const uint8_t first_app_key[16] = {
    // First AppKey
	0x8c, 0x32, 0x9f, 0x41, 0xd1, 0xd2, 0xc2, 0x9f,
	0x5a, 0xb7, 0x09, 0x0c, 0x0b, 0x31, 0x4d, 0x1d,
};

static const uint8_t second_app_key[16] = {
    0x88, 0xed, 0x35, 0xc4, 0x95, 0x01, 0xaf, 0x8a,
	0xce, 0x47, 0xd3, 0x11, 0xbf, 0x77, 0xb4, 0xc1,
};

static const uint8_t third_app_key[16] = {
	0x6a, 0x1a, 0xf1, 0xdb, 0xe8, 0x38, 0xdc, 0xf5,
	0x5c, 0x83, 0xa5, 0x33, 0x35, 0xd2, 0xe9, 0xde,
};

static uint16_t net_idx = 0;
static uint32_t iv_index = 0;
static uint8_t flags;
static bool needs_configuration = false;

uint16_t addr = 0x8000;

void configure()
{
	int res;
	uint8_t status = 0;

	if (needs_configuration)
	{
		if (addr == 0x8000)
		{
			LOG_ERR("Device hasn't been provisioned yet.");
			return;
		}

		LOG_INF("Configuring addr %d...", addr);

		res = bt_mesh_cfg_cli_net_key_add(net_idx, addr, net_idx, net_key, NULL);
		LOG_INF("NetKey %d: res %d, status = %d", net_idx, res, status);

		res = bt_mesh_cfg_cli_app_key_add(net_idx, addr, net_idx, 0, first_app_key, NULL);
		LOG_INF("AppKey 0: res %d, status = %d", res, status);

		res = bt_mesh_cfg_cli_app_key_add(net_idx, addr, net_idx, 1, second_app_key, NULL);
		LOG_INF("AppKey 1: res %d, status = %d", res, status);

		res = bt_mesh_cfg_cli_app_key_add(net_idx, addr, net_idx, 2, third_app_key, NULL);
		LOG_INF("AppKey 2: res %d, status = %d", res, status);

		LOG_INF("Configuration completed");
	}
}

void provision()
{

	int err;
	volatile uint32_t *node_addr  = (volatile uint32_t *) 0x10001080; // address node in UICR
	addr = *node_addr;
	/*err = sys_csrand_get(&addr, 2);
	if (err != 0)
	{
		LOG_ERR("Could not get a random address");
		return;
	}
	else
	{
		addr %= 0x7fff;
	}*/
	
	err = bt_mesh_provision(net_key, net_idx, flags, iv_index, addr, dev_key);
	if (err == -EALREADY)
	{
		LOG_INF("Using stored settings");
	}
	else if (err)
	{
		LOG_ERR("Provisioning failed (err %d)", err);
		return;
	}
	else
	{
		LOG_INF("Provisioning completed");
		// configure(addr);
	}
	needs_configuration = true;
}

I'm ready to add other information about my software if this can facilitate you to resolve my problem.

Thanks in advance for your answer