Note: Major API Changes. For older projects, you may use the v0.9 branch. Please see Migration notes
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. A minimal configuration for an SPP server on a MSP430 can run in 32 kB FLASH and only 4 kB of RAM.
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 daemon that connects to a Bluetooth module. Multiple applications can communicate with this daemon over different inter-process communication methods.
BTstack supports the Central and the Peripheral Role of Bluetooth 4.2 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.
Discussion and Community Support: BTstack Google Group
Protocols: L2CAP, RFCOMM, SDP, BNEP, ATT, SM (incl. LE Secure Connections).
Profiles GAP, IOP, HFP, HSP, SPP, PAN, GATT.
Coming next A2DP, AVRCP, HID, HOGP, BLE Mesh, and more.
It has been qualified with the the Bluetooth SIG for GAP, IOP, HFP, HSP, SPP, PAN profiles and GATT, SM of the Bluetooth 4.2 LE Central and Peripheral roles (QD ID 25340). For information on MFi/iAP2 support, please contact us.
| Status | Port | Platform |
|---|---|---|
 |
posix-h4 | Unix-based system connected to Bluetooth module 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-h5 | Unix-based system connected to Bluetooth module via H5 over serial port |
| No build server | posix-h5-bcm | Unix-based system connected to Broadcom/Cypress Bluetooth module via H5 over serial port |
 |
libusb | Unix-based system with dedicated USB Bluetooth dongle |
| No build server | windows-h4 | Win32-based system connected to Bluetooth module via serial port |
| No build server | windows-winusb | Win32-based system with dedicated USB Bluetooth dongle |
 |
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 |
 |
ios | daemon for iOS jailbreak devices, C client-server API |
| No build server | freertos | FreeRTOS: Run BTstack on a dedicated thread, not thread-safe. |
| Chipset | Type | HCI Transport | SCO over HCI (2) | BTstack folder | Comment |
|---|---|---|---|---|---|
| Atmel ATWILC3000 | Dual mode | H4 | Don't know | atwilc3000 | Firmware size: 270 kB |
| Broadcom UART | Dual mode | H4, H5 | Probably | bcm | Max UART baudrate 2 mbps |
| Broadcom USB Dongles | Dual mode | USB | Yes | bcm | |
| CSR UART | Dual mode | H4, H5, BCSP | No (didn't work) | csr | |
| CSR USB Dongles | Dual mode | USB | Yes | csr | |
| Dialog Semiconductor DA14581 | LE | H4, SPI | n.a. | da14581 | Official HCI firmware used |
| Espressif ESP32 | Dual mode | VHCI | Probably | SoC with Bluetooth and Wifi | |
| EM 9301, 9304 | LE | SPI | n.a. | em9301 | Custom HCI SPI implementation |
| Nordic nRF | LE | H4 | n.a. | Requires custom HCI firmware | |
| STM STLC2500D | Classic | H4 | No (didn't try) | stlc2500d | Custom deep sleep management not supported |
| Toshiba TC35661 | Dual mode | H4 | No (didn't try) | tc3566 | HCI version not tested. |
| TI CC256x, WL183x | Dual mode | H4, H5, eHCILL | Yes | cc256x | Also WL185x, WL187x, and WL189x |
More infos on supported chipsets
| Path | Description |
|---|---|
| chipset | Support for individual Bluetooth chipsets |
| doc | Sources for BTstack documentation |
| example | Example applications available for all ports |
| platform | Support for special OSs and/or MCU architectures |
| port | Complete port for a MCU + Chipset combinations |
| src | Bluetooth stack implementation |
| test | Unit and PTS tests |
| tool | Helper tools for BTstack |