BTstack is BlueKitchen's implementation of the official Bluetooth stack. It is well suited for small, resource-constraint devices such as 8 or 16 bit embedded systems as it is highly configurable and comes with an ultra small memory footprint.

Targeting a variety of platforms is as simple as providing the necessary UART, CPU, and CLOCK implementations. BTstack is currently capable of connecting to Bluetooth-modules via: (H2) HCI USB, (H4) HCI UART TI's eHCILL, and (H5) HCI Three-Wire UART.

On smaller embedded systems, a minimal run loop implementation allows to use BTstack without a Real Time OS (RTOS). If a RTOS is already provided, BTstack can be integrated and run as a single thread.

On larger systems, BTstack provides a server that connects to a Bluetooth module. Multiple applications can communicate with this server over different inter-process communication methods. As sockets are used for client/server communication, it's easy to interact via higher-level level languages, e.g. there's already a Java binding for use in desktop environments.

BTstack supports the Central and the Peripheral Role of Bluetooth 5 Low Energy specification incl. LE Secure Connections, LE Data Channels, and LE Data Length Extension. It can be configured to run as either single-mode stack or a dual-mode stack.

BTstack is free for non-commercial use. However, for commercial use, tell us a bit about your project to get a quote.

Documentation: HTML, PDF

Third-party libraries (FOSS): List of used libraries and their licenses

Discussion and Community Support: BTstack Google Group

Protocols: L2CAP (incl. Enhanced Retransmission Mode, LE Credit-Based Flow-Control Mode and LE Enhanced Credit-Based Flow-Control Mode), RFCOMM, SDP, BNEP, AVDTP, AVCTP, ATT, SM (incl. LE Secure Connections and Cross-Transport Key Derivation).

Profiles: A2DP, AVRCP incl. Browsing (CT TG) and Cover Art (CT), GAP, GATT, HFP, HID, HSP, IOP, MAP, OPP, SPP, PAN, PBAP.

GATT Service Servers: Battery (BAS), Bond Management (BMS), Cycling Power (CPS), Cycling Speed and Cadence (CSCS), Device Information (DID), Heart Rate (HRS), HID over GATT (HIDS) Device, Immediate Alert, Link Loss (LLS), Mesh Provisioning, Mesh Proxy, Nordic SPP, Scan Parameters (SCPS), TX Power (TPS), u-Blox SPP.

GATT Service Clients:: ANCS, Battery (BAS), Device Information (DID), HID-over-GATT (HOGP) Host, Immediate Alert, Link Loss, Scan Parameters (SCPP), TX Power (TXS).

LE Audio Profiles: Object Transfer Profile (OTP), Volume Control Profile (VCP), Microphone Control Profile (MICP), Media Control Profile (MCP), Call Control Profile (CCP), Coordinated Set Identification Profile (CSIP), Basic Audio Profile (BAP), Common Audio Profile (CAP), Hearing Access Profile (HAP), Telephony and Media Audio Profile (TMAP), Public Broadcast Profile (PBP), Gaming Audio Profile (GMAP)

LE Audio Services: Audio Input Control Service (AICS), Volume Offset Control Service (VOCS), Volume Control Service (VCS), Microphone Control Service (MICS), Media Control Service (MCS), Generic Media Control Service (GMCS), Telephony Bearer Service (TBS), Coordinated Set Identification Service (CSIS), Published Audio Capabilities Service (PACS), Audio Stream Control Service (ASCS), Broadcast Audio Scan Service (BASS), Common Audio Service (CAS), and Hearing Access Service (HAS).

GATT Services are in general easy to implement and require short development time. For more GATT Services please contact us, or follow the implementation guidelines.

Qualification: BTstack been qualified with the Bluetooth SIG (DN Q331293) for ATT, GAP, GATT, IOP, L2CAP, SDP, SM of the Bluetooth Core 6.0 specification as well as A2DP 1.4, AICS 1.0, ASCS 1.0.1, AVCTP 1.4, AVDTP 1.3, AVRCP 1.6.3, BAP 1.0.2, BAS 1.1, BASS 1.0, BAU 1.0, BNEP 1.0, CAP 1.0, CAS 1.0, CCP 1.0, CPP 1.1, CPS 1.1, CSCP 1.0, CSCS 1.0, CSIP 1.0.1, CSIS 1.0.1, DID 1.3, DIS 1.1, GAVDP 1.3, GMAP 1.0, GMCS 1.0.1, HAP 1.0, HAS 1.0, HFP 1.9, HID 1.1.1, HIDS 1.0, HOGP 1.0, HRP 1.0, HRS 1.0, HSP 1.2, IAS 1.0, LC3 1.0.1, LLS 1.0, MAP 1.4.2, MCP 1.0, MCS 1.0.1, MICP 1.0, MICS 1.0, OPP 1.2.1, OTP 1.0, OTS 1.0, PACS 1.0.1, PANP 1.0, PBAP 1.2.3, PBP 1.0, RFCOMM 1.2, SPP 1.2, SPS 1.0, TBS 1.0, TMAP 1.0, TxPS 1.0, VCP 1.0, VCS 1.0, VOCS 1.0.

For information on Apple's MFi/iAP2 and Find My profiles or access to LE Audio, MAP, PBAP Server, please contact us directly.

Build Status	Port	Platform
	esp32	Espressif ESP32 2.4 GHz Wi-Fi and Bluetooth Dual-Mode combo chip using FreeRTOS
	max32630-fthr	MAX32630FTHR ARM Cortex M4F Board with onboard Panasonic PAN1326 module containing TI CC2564B Bluetooth controller
	msp432p401lp-cc256x	TI MSP432P401R LaunchPad with CC2564C Dual-mode Bluetooth® Controller Evaluation Module and EM Adapter BoosterPack with additional 32768Hz quartz oscillator
No build server	rrenesas-ek-ra6m4a-da14531	Renesas EK-RA6M4 with MikroeE BLE Tiny Click board
No build server	renesas-tb-s1ja-cc256x	Renesas TB-S1JA with with Dual-mode Bluetooth® CC2564 evaluation board and EM Adapter BoosterPack with additional 32768Hz quartz oscillator
	samv71-xplained-atwilc3000	SAMV71 Ultra Xplained Ultra evaluation kit with ATWILC3000 SHIELD
	stm32-f4discovery-cc2564b	STM32 F4 Discovery Board with CC256xEM Bluetooth Adapter Kit for ST and CC2564B Dual-mode Bluetooth® Controller Evaluation Module
	stm32-l073rz-nucleo-em9304	EM9304 DVK: STM32 Nucleo development board NUCELO-L73RZ with EM9304 Bluetooth Controller
No build server	stm32-wb55xx-nucleo-freertos	P-NUCLEO-WB55 kit
	wiced-h4	Broadcom/Cypress platforms that support the WICED SDK via H4 UART, e.g. RedBear Duo (BCM43438 A1), Inventek Systems ISM4334x (BCM43438 A1), Inventek Systems ISM4343 (BCM43340)

Status	Port	Platform
No build server	freebsd-netgraph	FreeBSD port that uses kernel netgraph HCI node
	libusb	Unix-based system with dedicated USB Bluetooth dongle
No build server	libusb-intel	Unix-based system with Intel Wireless 8260/8265 Controller
	posix-h4	Unix-based system connected to Bluetooth module via H4 over serial port
No build server	posix-h4-nxp	Unix-based system connected to Cypress controllers via H4 over serial port
No build server	posix-h4-da14581	Unix-based system connected to Dialog Semiconductor DA14581 via H4 over serial port
No build server	posix-h4-da14585	Unix-based system connected to Dialog Semiconductor DA14585 via H4 over serial port
No build server	posix-h4-nxp	Unix-based system connected to NXP controllers via H4 over serial port
No build server	posix-h4-zephyr	Unix-based system connected to Bluetooth module with Zephyr HCI firmware via H4 over serial port
No build server	posix-h5	Unix-based system connected to Bluetooth module via H5 over serial port
No build server	qt-h4	Unix- or Win32-based Qt application connected to Bluetooth module via H4 over serial port
No build server	qt-usb	Unix- or Win32-based Qt application with dedicated USB Bluetooth dongle
No build server	windows-h4	Win32-based system connected to Bluetooth module via serial port
No build server	windows-h4-da14585	Win32-based system connected to Dialog Semiconductor DA14585 via H4 over serial port
No build server	windows-winusb	Win32-based system with dedicated USB Bluetooth dongle
No build server	windows-winusb-intel	Win32-based system with Intel Wireless 8260/8265 Controller
No build server	raspi	Raspberry Pi 3 or Raspberry Pi Zero W with built-in BCM4343 Bluetooth/Wifi Controller
	daemon	TCP and Unix domain named socket client-server architecture supporting multiple clients
	java	Java wrapper for daemon
	mtk	daemon for rooted Android devices, based on Mediatek MT65xx processor, Java and C client-server API
No build server	freertos	FreeRTOS: Run BTstack on a dedicated thread, not thread-safe.

More infos on supported chipsets