samples/bluetooth/direction_finding_peripheral/src/main.c

/*
 * Copyright (c) 2022 Nordic Semiconductor ASA
 *
 *  SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/types.h>
#include <stddef.h>
#include <string.h>
#include <errno.h>
#include <zephyr/sys/printk.h>
#include <zephyr/sys/byteorder.h>
#include <zephyr/kernel.h>

#include <zephyr/bluetooth/bluetooth.h>
#include <zephyr/bluetooth/hci.h>
#include <zephyr/bluetooth/conn.h>
#include <zephyr/bluetooth/uuid.h>
#include <zephyr/bluetooth/gatt.h>
#include <zephyr/bluetooth/services/bas.h>
#include <zephyr/bluetooth/services/hrs.h>
#include <zephyr/bluetooth/direction.h>

#define DF_FEAT_ENABLED BIT64(BT_LE_FEAT_BIT_CONN_CTE_RESP)

static const struct bt_data ad[] = {
	BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
	BT_DATA_BYTES(BT_DATA_LE_SUPPORTED_FEATURES, BT_LE_SUPP_FEAT_24_ENCODE(DF_FEAT_ENABLED)),
};

/* Latency set to zero, to enforce PDU exchange every connection event */
#define CONN_LATENCY 0U
/* Interval used to run CTE request procedure periodically.
 * Value is a number of connection events.
 */
#define CTE_REQ_INTERVAL (CONN_LATENCY + 10U)
/* Length of CTE in unit of 8 us */
#define CTE_LEN (0x14U)

#if defined(CONFIG_BT_DF_CTE_TX_AOD)
static const uint8_t ant_patterns[] = { 0x2, 0x0, 0x5, 0x6, 0x1, 0x4, 0xC, 0x9, 0xE, 0xD, 0x8 };
#endif /* CONFIG_BT_DF_CTE_TX_AOD */

static void enable_cte_response(struct bt_conn *conn)
{
	int err;

	const struct bt_df_conn_cte_tx_param cte_tx_params = {
#if defined(CONFIG_BT_DF_CTE_TX_AOD)
		.cte_types = BT_DF_CTE_TYPE_ALL,
		.num_ant_ids = ARRAY_SIZE(ant_patterns),
		.ant_ids = ant_patterns,
#else
		.cte_types = BT_DF_CTE_TYPE_AOA,
#endif /* CONFIG_BT_DF_CTE_TX_AOD */
	};

	printk("Set CTE transmission params...");
	err = bt_df_set_conn_cte_tx_param(conn, &cte_tx_params);
	if (err) {
		printk("failed (err %d)\n", err);
		return;
	}
	printk("success.\n");

	printk("Set CTE response enable...");
	err = bt_df_conn_cte_rsp_enable(conn);
	if (err) {
		printk("failed (err %d).\n", err);
		return;
	}
	printk("success.\n");
}

static void connected(struct bt_conn *conn, uint8_t err)
{
	if (err) {
		printk("Connection failed (err 0x%02x)\n", err);
	} else {
		printk("Connected\n");
	}

	enable_cte_response(conn);
}

static void disconnected(struct bt_conn *conn, uint8_t reason)
{
	printk("Disconnected (reason 0x%02x)\n", reason);
}

BT_CONN_CB_DEFINE(conn_callbacks) = {
	.connected = connected,
	.disconnected = disconnected,
};

static void bt_ready(void)
{
	int err;

	printk("Bluetooth initialized\n");

	err = bt_le_adv_start(BT_LE_ADV_CONN_NAME, ad, ARRAY_SIZE(ad), NULL, 0);
	if (err) {
		printk("Advertising failed to start (err %d)\n", err);
		return;
	}

	printk("Advertising successfully started\n");
}

void main(void)
{
	int err;

	err = bt_enable(NULL);
	if (err) {
		printk("Bluetooth init failed (err %d)\n", err);
		return;
	}

	bt_ready();
}