Cygnet takes flight today! While in real life a cygnet is a baby swan, at Blues we prefer to think of our Cygnet as a less expensive, but perfectly capable, cousin to the Blues Swan.
What is Blues Cygnet?
Like the Blues Swan, Cygnet is an Adafruit Feather-compatible host based on an STM32 microcontroller. It's a perfect companion to the Blues Notecarrier F, which includes a Feather-compatible socket.
Cygnet is built around ST's ultra low-power STM32L433 and offers 256KB of flash memory and 64KB of RAM. Like Swan, Cygnet has an onboard Qwiic/StemmaQT connector, but also provides a USB C connector (instead of micro USB).
The board has three independent power options – USB, battery, or line power – and provides a software-switchable 2 Amp regulator for powering external sensors. When operating in its low-power operating mode, the entire Cygnet board draws only 4uA while retaining all of its memory, making it ideal for battery-powered devices.
Key Cygnet Specs and Comparison with Swan
Cygnet includes the following features and capabilities:
- Ultra low-power Arm Cortex-M4 core clocked at 80Mhz
- STM32L433-based microcontroller
- 256KB of flash and 64KB of RAM
- Feather-compatible GPIO & Bus pins including:
- RX & TX
- SDA & SCL
- SCK/MOSI/MISO
- I2C
- Qwiic/StemmaQT connector
- USB C connector
- Support for Notecard Outboard Firmware Update
When comparing Cygnet and Swan for your specific products' needs, consult the following table:
| Swan | Cygnet | |
|---|---|---|
| SOM Type | STM32L4R5 | STM32L433 |
| Cortex CPU Type | M4 | M4 |
| Flash Size | 2048KB | 256KB |
| SRAM Size | 640KB | 64KB |
| STOP2 RTC XTAL | ✅ | ✅ |
| STOP2 Sleep Current | 8uA | 4uA |
| QWIIC Connector | ✅ | ✅ |
| Cortex Debug Connector | ✅ | ✅ |
| 3V3 Output Enable | ✅ | ✅ |
| 3V3 Output Capacity | 2A | 2A |
| USB Connector Type | Micro USB | USB C |
| PCB Pin Castellations | ✅ | ✅ |
| PCB Pins | 65 | 28 |
| Notecard Outboard Firmware Update | ✅ | ✅ |
| Arduino Native Debugging | ✅ | ✅ |
| Price | $25 | $15 |
Programming Cygnet
Cygnet ships today with support for C/C++ and Arduino (with CircuitPython support coming soon!). You can program Cygnet using Arduino IDE, STM32CubeIDE with an optional SWD programmer, or PlatformIO (coming soon!).
Debugging Cygnet
Since Cygnet includes a CORTEX Debug connector, you can take advantage of debugging frameworks and tooling such as STLINK, JLink, OpenOCD, or GDB.
What's more, like Swan, Cygnet supports step debugging with Arduino Native Debugging on Arduino IDE v2 using an attached STLINK programmer/debugger.
Getting Started with Cygnet
Buy your own flock of Cygnets on the Blues shop today for only $15 each. While you're waiting, peruse the Cygnet datasheet and follow the Arduino IDE quickstart when your Cygnet arrives.
Happy Hacking! 🦢
