c034fbca54
Instead of attempting to allocate multiple advertisement instances, only use one by default. If needed, a NewAdvertisement method could be added in the future for devices that actually do support multiple advertisements at a time. The motivation for this change is fix an inconsistency with the nrf51 (which already had the behavior of DefaultAdvertisement) and the discovery that nrf52 devices also don't seem to support more than one advertisement instance, even though their API does allow for multiple instances. But the primary motivation is that for consistency with hosted systems, it would be best if the nrf port would automatically re-enable advertisement when a connection is lost (or made). While BlueZ does support more than one instance, it is implemented by simply iterating through the active advertisement instances so could also be implemented by doing that manually. I haven't checked the behavior of Windows and MacOS - but as always, the API is not yet stable and can be changed if needed. |
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|---|---|---|
| .circleci | ||
| examples | ||
| s110_nrf51_8.0.0 | ||
| s132_nrf52_6.1.1 | ||
| s140_nrf52_7.0.1 | ||
| winbt | ||
| .gitattributes | ||
| .gitignore | ||
| adapter.go | ||
| adapter_linux.go | ||
| adapter_nrf51.go | ||
| adapter_nrf528xx.go | ||
| adapter_s110.c | ||
| adapter_s110.go | ||
| adapter_s132.c | ||
| adapter_s132.go | ||
| adapter_s140.c | ||
| adapter_s140.go | ||
| adapter_sd.go | ||
| adapter_windows.go | ||
| error_sd.go | ||
| gap.go | ||
| gap_linux.go | ||
| gap_nrf51.go | ||
| gap_nrf528xx.go | ||
| gap_windows.go | ||
| gatts.go | ||
| gatts_linux.go | ||
| gatts_sd.go | ||
| go.mod | ||
| go.sum | ||
| LICENSE | ||
| mac.go | ||
| Makefile | ||
| README.md | ||
| uuid.go | ||
| uuid_sd.go | ||
| uuid_test.go | ||
Go Bluetooth
This package attempts to build a cross-platform Bluetooth Low Energy module for Go. It currently supports the following systems:
| Windows | Linux | Nordic chips | |
|---|---|---|---|
| API used | WinRT | BlueZ (over D-Bus) | SoftDevice |
| Scanning | ✔️ | ✔️ | ✔️ |
| Advertisement | ❌ | ✔️ | ✔️ |
| Local services | ❌ | ✔️ | ✔️ |
| Local characteristics | ❌ | ❌ | ✔️ |
Baremetal support
As you can see above, there is support for some chips from Nordic Semiconductors. At the moment the following chips are supported:
- The nRF52832 with the S132 SoftDevice (version 6).
- The nRF52840 with the S140 SoftDevice (version 7).
- The nRF51822 with the S110 SoftDevice (version 8). This SoftDevice does not support all features (e.g. scanning).
These chips are supported through TinyGo.
The SoftDevice is a binary blob that implements the BLE stack. There are other (open source) BLE stacks, but the SoftDevices are pretty solid and have all the qualifications you might need. Other BLE stacks might be added in the future.
Flashing the SoftDevice
Flashing the SoftDevice can be tricky. If you have nrfjprog installed, you can erase the flash and flash the new BLE firmware using the following commands. Replace the path to the hex file with the correct SoftDevice, for example s132_nrf52_6.1.1/s132_nrf52_6.1.1_softdevice.hex for S132 version 6.
nrfjprog -f nrf52 --eraseall
nrfjprog -f nrf52 --program path/to/softdevice.hex
After that, don't reset the board but instead flash a new program to it. For example, you can flash the Heart Rate Sensor example using tinygo (modify the -target flag as needed for your board):
tinygo flash -target=pca10040-s132v6 ./examples/heartrate
Flashing will normally reset the board.
For boards that use the CMSIS-DAP interface (such as the BBC micro:bit), this works a bit different. Flashing the SoftDevice is done by simply copying the .hex file to the device, for example (on Linux):
cp path/to/softdevice.hex /media/yourusername/MICROBIT/
Flashing will then need to be done a bit differently, using the CMSIS-DAP interface instead of the mass-storage interface normally used by TinyGo:
tinygo flash -target=microbit-s110v8 -programmer=cmsis-dap ./examples/heartrate
API stability
The API is not stable! Because many features are not yet implemented and some platforms (e.g. MacOS) are not yet supported, it's hard to say what a good API will be. Therefore, if you want stability you should pick a particular git commit and use that. Go modules can be useful for this purpose.
Some things that will probably change:
- Add options to the
Scanmethod, for example to filter on UUID. - Connect/disconnect events.
- The behavior around advertisement. Nordic SoftDevices stop advertising when a device connects, which is somewhat unintuitive.
License
This project is licensed under the BSD 3-clause license, see the LICENSE file for details.
The SoftDevices from Nordic are licensed under a different license, check the license file in the SoftDevice source directory.