Developing Bluetooth Applications
Bluetooth applications are developed using the general architecture and methods described described in the “Application Development” section of the documentation.
Additional information related solely to Bluetooth applications can be found on this page.
Thread Safety
Unless otherwise specified in the documentation of the API functions, calling the Bluetooth API is thread-safe.
Initialization
The Bluetooth subsystem is initialized using the bt_enable()
function. The caller should ensure that function succeeds by checking
the return code for errors. If a function pointer is passed to
bt_enable(), the initialization proceeds asynchronously, and the
completion is notified through the given function.
Bluetooth Application Example
Below is a demonstration of a simple Bluetooth beacon application. This application initializes the Bluetooth subsystem and enables non-connectable advertising.
#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
#ifndef IBEACON_RSSI
#define IBEACON_RSSI 0xc8
#endif
/*
* Set iBeacon demo advertisement data. These values are for
* demonstration only and must be changed for production environments!
*
* UUID: 18ee1516-016b-4bec-ad96-bcb96d166e97
* Major: 0
* Minor: 0
* RSSI: -56 dBm
*/
static const struct bt_data ad[] = {
BT_DATA_BYTES(BT_DATA_FLAGS, BT_LE_AD_NO_BREDR),
BT_DATA_BYTES(BT_DATA_MANUFACTURER_DATA,
0x4c, 0x00, /* Apple */
0x02, 0x15, /* iBeacon */
0x18, 0xee, 0x15, 0x16, /* UUID[15..12] */
0x01, 0x6b, /* UUID[11..10] */
0x4b, 0xec, /* UUID[9..8] */
0xad, 0x96, /* UUID[7..6] */
0xbc, 0xb9, 0x6d, 0x16, 0x6e, 0x97, /* UUID[5..0] */
0x00, 0x00, /* Major */
0x00, 0x00, /* Minor */
IBEACON_RSSI) /* Calibrated RSSI @ 1m */
};
static void bt_ready(int err)
{
if (err) {
printk("Bluetooth init failed (err %d)\n", err);
return;
}
printk("Bluetooth initialized\n");
/* Start advertising */
err = bt_le_adv_start(BT_LE_ADV_NCONN, ad, ARRAY_SIZE(ad),
NULL, 0);
if (err) {
printk("Advertising failed to start (err %d)\n", err);
return;
}
printk("iBeacon started\n");
}
int main(void)
{
int err;
printk("Starting iBeacon Demo\n");
/* Initialize the Bluetooth Subsystem */
err = bt_enable(bt_ready);
if (err) {
printk("Bluetooth init failed (err %d)\n", err);
}
return 0;
}
The key APIs employed by the beacon sample are bt_enable() for initializing Bluetooth, followed by bt_le_adv_start() for starting the advertisement with a specific combination of advertising and scan response data.
Compilation and Download
Run the wm.py build command
cd examples/bluetooth/ibeacon
wm.py build
After successful building, the generated firmware ibeacon.fls will be located in:
examples/bluetooth/ibeacon/build/ibeacon.fls
Provide the location or refer to the Quick Start Guide section for downloading the firmware.Upon successful downloading, the console will print information as follows:
I/bt_hci_core [0.090] Identity: 38:65:BD:12:21:66 (public)
I/bt_hci_core [0.096] HCI: version 4.2 (0x08) revision 0x0709, manufacturer 0x070c
I/bt_hci_core [0.104] LMP: version 4.2 (0x08) subver 0x0709
Bluetooth initialized
iBeacon started
More Application Examples
For more application examples, please refer to examples/bluetooth