Signaloid C0-microSD is an FPGA development board based on the popular iCE40 FPGA from Lattice Semiconductor in a microSD form factor.

You can use it to prototype your designs on a breadboard using a microSD breakout board or integrate it into your new PCB designs by adding a dedicated microSD slot, using the available pins as GPIO. You can even plug the Signaloid C0-microSD into an existing platform that supports microSD cards (like the Bee Data Logger or the Adafruit Adalogger) and use it as a co-processor.

A Versatile New FPGA Platform

When plugged into a host computer, the Signaloid C0-microSD appears as an empty and unformatted SD storage device. However, you can easily load your custom FPGA design bitstreams to the Signaloid C0-microSD via the SD interface from the host computer.

If you don’t wish to load a custom core design, the Signaloid C0-microSD comes preloaded with a version of Signaloid’s C0 RISC-V processor core, which you can use to run applications. In this mode, host computers can use the SD protocol to exchange data with applications running on the Signaloid C0-microSD, either by creating custom applications that run on the host platform and that access the SD storage device, or using Unix tools such as dd.

Applications running on the Signaloid’s C0 processor core in the Signaloid C0-microSD can take advantage of a subset of Signaloid’s uncertainty-tracking technology to quantify how uncertainties in data affect their outputs.

This Crowd Supply campaign will also feature the Signaloid SD-Dev, an optional compact carrier board and development system for testing and characterizing the Signaloid C0-microSD. You can use it to connect your Signaloid C0-microSD to your computer as a peripheral or add on a Raspberry Pi CM4 to produce a compact SBC with hot-swappable FPGA modules in a standalone configuration.

Features & Specifications:

C0-microSD

Lattice ICE40UP5K FPGA
5280 logic cells
120 Kbit dual-port Block RAM
1 Mbit (128 KB) single-port RAM
Renesas AT25QL128A SPI Flash
128 Mbit (16 MB) non-volatile memory
Programmable I/O pins:
Two on-board leds (one red and one green), for status indication.
Six programmable I/O pins (from the microSD interface)
Five additional programmable pins on test pads
Built-in Signaloid C0 RISC-V processor core
Built-in bootloader, allowing you to load new FPGA bitstreams or RISC-V applications via the SD interface

SD-Dev
Compact design with plentiful I/O:
2 USB-C downstream ports
1 USB-C upstream port
1 USB-C upstream power-only port
1 Micro HDMI port
JST connectors for SPI and I2C peripherals
One full-size SD and one microSD slot for a Signaloid C0-microSD or for regular SD storage cards
SD card detection
Programmable power cycling
Power measurement
Open-top microSD socket allows you to probe the Signaloid C0-microSD debug pads
Dual function (peripheral and standalone mode)
Board outline of 57 mm x 57 mm

Open Source

PDFs of the schematic and the layout layers, as well as source code examples, will be released in a public GitHub repository before the campaign starts.
The Signaloid C0-microSD is compatible with existing open-source toolchains that can target the iCE40 FPGA, such as Icestorm, Yosys, NextPnR, and Icestudio. We also plan on supporting AmarathHDL, and LiteX.