Silicon Witchery S1 module combines nRF52811 Bluetooth SoC with Lattice iCE40 FPGA

Sweden-based Silicon Witchery S1 is a tiny module combining Nordic Semi nRF52811 Bluetooth LE SoC with Lattice Semi iCE40 FPGA designed for battery-powered applications leveraging DSP and machine learning (ML) at the edge.

The S1 module features just four key components in a tiny 11.5 x 6 mm form factor and targets applications requiring “demanding” algorithms while consuming as little energy as possible.

Silicon Witchery S1 module with nFR52840 and FPGA

Silicon Witchery S1 module specifications:

  • MCU – Nordic Semi nRF52811 Arm Cortex-M4 MCU @ 64 MHz with Bluetooth 5.2 support including Long Range, Thread support.
  • FPGA – Lattice Semi iCE40 FPGA with 5k LUT and DSP blocks.
  • Storage – 32 Mbit flash storage.
  • Integrated antenna, passives, and crystals.
  • I/Os – 20x castellated holes with
    • 8x FPGA IO include I3C, I2C, SPI, and USB.
    • 2x nRF GPIO pins with ADC and low power wake.
    • SWD pins for debugging
  • Power Supply
    • Lithium battery charging and monitoring.
    • 3x adjustable Vout rails including 1x buck-boost up to 5.5V
  • Dimensions – 11.5 x 6 mm


Silicon-Witchery S1 block diagram

The company provides a lightweight SDK based on the Nordic nRF5 SDK, and that relies on tools such as yosys, icestorm & NextPNR, as well as two open-source hardware development kits with the battery-powered S1 Popout board with Stemma/Qwicc QT connector for Adafruit and Sparkfun modules, and the S1 ECG kit with Analog AD8233 front-end designed to research ML-based ECG algorithms.

Use cases include high speed & time-critical DSP, pre-processing data on the edge, power-efficient algorithm design, parallel data processing, real-time AI inferencing, remote machine learning, Bespoke AI algorithm deployment, and Bespoke DSP algorithm deployment.

S1 Popout board & S1 ECG kit

You’ll find documentation and instructions to get started with the module and the two development kits on the documentation website.

The nRF52811 + FPGA S1 module is sold for $30, the S1 Popout board for $39, and the S1 ECG Kit for $45 on Digikey. Additional information may be found on the company’s website.


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2 years ago

Using nRF52840 and not using its own built-in USB, relying instead on FPGA? What a wasteful oversight.

Stefan Brüns
2 years ago

As it is an nRF52811 only which does not have USB, this is ok as an option (you don´t have to use it, after all). But putting the differential pair 4 pins apart, with two GPIOs inbetween is just stupid.

joakim bergman
joakim bergman
2 years ago

Datasheet and video say  Nordic nRF52811 !?

Tyler Larson
2 years ago

I’m struggling to come up with a class of use cases for this hardware combination. I’m sure combining a bluetooth SoC plus an FPGA is exactly what SOMEONE is looking for, but I can’t imagine who. What’s the target audience for this product?

Khadas VIM4 SBC