Cygnet is a low-cost embeddable STM32L4+-based microcontroller board designed to accelerate the development and deployment of battery-powered IoT solutions.
As a lower-cost alternative to the Swan, Cygnet still provides an extensive feature set required for edge-based inferencing and remote monitoring applications. Like its more expensive sibling, Cygnet is designed to be the ideal companion to Notecard while offering a more budget-friendly option.
Functional Description
Cygnet is a Feather-compatible STM32-based MCU, and a lower-cost alternative to our popular Swan MCU. Like the Swan, Cygnet is offered in a Feather standard form factor and uses a STM32L4 part while still providing plenty of flash and RAM to run the majority of your Notecard-powered applications.
Features
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Features of the ST STM32L433CC microcontroller
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80MHz Clock speed
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256KB Flash, proprietary code readout protection
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64KB of SRAM including 64KB with hardware parity check
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Ultra-low-power with FlexPowerControl
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11x timers
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16x communication interfaces
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14-channel DMA controller
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Rich analog peripherals (independent supply)
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True random number generator
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-
Compliant with the Adafruit Feather Specification
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Includes a USB-C port for easy power and serial connectivity
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Includes a PMIC accessible via a JST PH connector, allowing you to either power the board via a LiPo battery and/or recharge the battery via USB.
-
-
USER_BTN
programmable button -
LED_BUILTIN
programmable LED (red) -
JTAG (SWD capable) debug jack
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BOOT and RESET buttons
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Modular design supports Feather pins or an expansion PCB (to break pins out to 0.1" headers for easier wiring and debugging).
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10kΩ pull-ups on the
SDA
andSCL
pins -
Qwiic connector
Package Configuration
The Cygnet can be used as a Feather-compatible board with soldered male headers, as a part of the Blues Notecard Feather dev kit.
Feather-compatible Cygnet
Out of the box, the Cygnet is usable as a Feather-compatible device.
Pin Information
The following tables contain pin definition mappings between the Cygnet Feather pins to the STM32L433 core MCU.
Cygnet Feather to STM32 Mapping
Pin # | Pin Name | Pin # | Pin Name | |
---|---|---|---|---|
RST | RST# | ---- | ||
3V3 | ---- | |||
AREF | ---- | |||
GND | ---- | |||
PA0 | A0 | BAT | ||
PA1 | A1 | PH0 | EN | |
PA2 | A2 | PB3 | USB | |
PA3 | A3 | PB4 | D13 | |
PB1 | A4 | PB15 | D12 | |
PA7 | A5 | PB0 | D11 | |
PA5 | CK | PB13 | D10 | |
PB5 | MO | PB14 | D9 | |
PA6 | MI | PB9 | D6 | |
PA10 | RX | PB8 | D5 | |
PA9 | TX | PB6 | SCL | |
PH3 | B | PB7 | SDA | |
PC13 | USER_BTN | PA8 | LED_BUILTIN |
Pin Description Table
Pin Name | Pin Description (Primary) | Voltage Tolerance |
---|---|---|
A0 | I/O - GPIO, PWM, ADC | 5V |
A1 | I/O - GPIO, PWM, ADC | 5V |
A2 | I/O - GPIO, PWM, ADC | 5V |
A3 | I/O - GPIO, PWM, ADC | 3.6V |
A4 | I/O - GPIO, PWM, ADC | 5V |
A5 | I/O - GPIO, ADC | 5V |
D5 | I/O - GPIO | 5V |
D6 | I/O - GPIO | 5V |
D9 | I/O - GPIO, PWM | 5V |
D10 | I/O - GPIO, ADC | 5V |
D11 | I/O - GPIO, PWM, ADC | 5V |
D12 | I/O - GPIO, PWM, ADC | 5V |
D13 | I/O - GPIO, ADC | 5V |
SCL | I²C - Serial Clock | 5V |
SDA | I²C - Serial Data | 5V |
3V3 | Power - Constant 3.3V Supply | - |
EN | Power - Chip Enable | 5V |
GND | Power - Ground | - |
RST | Power - Reset | - |
BAT | Power - Battery Voltage Supply | - |
AREF | Power - Reference Voltage | - |
USB | Power - USB Voltage Supply | - |
RX | Serial - Receive | 5V |
TX | Serial - Transmit | 5V |
B | Boot0 - Boot into Bootloader | - |
MI | SPI - Main In Secondary Out | 5V |
MO | SPI - Main Out Secondary In | 5V |
CK | SPI - Serial Clock, DAC | 3.6V |
USER_BTN | User Button | - |
LED_BUILTIN | Built-in LED | - |
NOTE: All digital I/O pins are interrupt capable.
Specifications
Electrical Characteristics
DC Characteristics
Description | Minimum | Maximum | Unit |
---|---|---|---|
VIN Supply Voltage | 2.5 | 5.5 | V |
VBAT Supply Voltage | 2.5 | 5.5 | V |
VUSB Supply Voltage | 2.5 | 5.5 | V |
Supply Current | 0.5 | 2.0 | A |
3V3 Output @ 5V | 1.07 | 2.09 | A |
Absolute Maximum Ratings
Description | Minimum | Maximum | Unit |
---|---|---|---|
Operating temperature | -40 | 125 | °C |
Ordering Information
- Please visit the Cygnet product page for ordering information.
Design Files
Open source hardware designs for the Swan and all Blues Hardware are maintained in the note-hardware GitHub repository.
Terms and Conditions
Visit Blues Hardware Terms & Conditions.
Revision History
Author | Date | Summary |
---|---|---|
Alex R. Bucknall | 10 DEC 2024 | Document drafted |
Contact Information
For other questions about the Cygnet, visit the Blues Forum.
Blues Inc.
https://blues.com
50 Dunham Ridge Suite 1650
Beverly, MA 01915
support@blues.com