There has recently been a desire and surge in the development of standalone portable hardware development kits with qwerty keyboards and displays all fitted into a smartphone/blackberry-like (with trackpads) form factors, either for the sake of portability, or security and ease of use. One of the recent boards developed on these premises is the precursor; a recently announced FPGA development kit.

Developed by Sutajio Ko-usagi, the company behind several projects like the Fomu FPGA Board,  the Precursor is designed to serve as an all-in-one, powerful but portable, open hardware development platform for secure, mobile computation and communication.

Packed in a pocket friendly 69 mm x 138 mm x 7.2 mm size with a smartphone look, the Precursor, comes with a built-in display, a physical keyboard, and an internal battery which powers the on-board, FPGA-hosted (Xilinx XC7S50 based), soft-core System-on-Chip (SoC).

The goal of the precursor according to the product announcement was to create a solution that was truly portable but also secure and powerful enough for use in security- and privacy-critical applications. To achieve this, the company designed a SOC called “Betrusted-SoC,” which is meant to be the central pillar of security for devices like Precursor.

The version of Betrusted-SoC used in Precursor is based on a Xilinx FPGA and some of the features include:

  • XC7S50-1L CSG324I, 80% utilized as of October 2020
  • 100 MHz customized VexRISC-V RV32IMAC + MMU core with 4k caches
  • Crypto primitives
    • Ring oscillator TRNG (compliments off-chip TRNG)
    • JTAG-based self-fusing for on-chip generation and sealing of secret keys
    • AES-128, -192, -256 with ECB, CBC and CTR modes
    • SHA-2 and SHA-512 digests
    • Microcode Curve25519 field arithmetic engine
  • SPI
    • High speed, 100 MHz DDR OPI SPI interface for code ROM
    • Low speed, 20 MHz SDR 1-bit SPI interface to an insecure domain
  • I²C (100 kHz) for system integration
  • Keyboard switch matrix controller with low power standby
  • Bidirectional I²S interface for audio
  • Custom frame buffer-based LCD interface
  • 32-bit async SRAM interface with standby support
  • Standard UART
  • Full speed USB device
  • Hardware Ticktimer
  • 12-bit ADC (system voltage monitor)
  • GPIO for power management and extension


About The Author

Muhammad Bilal

I am highly skilled and motivated individual with a Master's degree in Computer Science. I have extensive experience in technical writing and a deep understanding of SEO practices.

Scroll to Top