GR740 Single Board Computer Reference Design




The GR740 SBC is a reference design and basic software for a single board computer based on the rad-hard GR740 Quad-Core LEON4 SPARC V8 Processor and the Microchip RTG4 radiation tolerant FPGA.  The reference design data package consists of schematics and other design files required for developing a single board computer for flight.  Moreover, developers can access (under licensing conditions) a set of software products like boot software, RTEMS5-SMP OS and device drivers, test application and EGSE software.

The design package has been developed within an ESA activity that saw Gaisler and Beyond Gravity as the main actors. The board developed during the activity does not qualify for flight but a Qualification Test Plan has been established in view of a future space qualification.

The objectives for a reference design are to reduce the risk associated with new developments and create a seed to a European offering of off-the-shelf space computers at higher technology readiness level. The availability of the reference design enables a shorter development route to a flight board. The basic software package supports board-bring up for new developers. 





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Board Format

Compact PCI Serial Space backplane standard (CPCI-S.1 R1.0) with 6U form factor

  • The board can be tailored to fit into both system or payload slot

Processing capabilities

GR740 radiation-hardened SoC

  • Parallel boot: MRAM 64 KiB
  • Application storage: SPI Flash memory, 32 MiB
  • Volatile working memory: SDRAM, 512 MiB + ECC check bits 
  • PCI, UART and GPIO, interfaces with the RTG4 FPGA

Microsemi RTG4 radiation tolerant FPGA

  • Adds memory interfaces and high-speed serial link (HSSL) capability to the SBC
  • Volatile working memory: 3D-PLUS DDR2, 512 MiB data RAM plus ECC
  • Data Storage: 3D-PLUS NAND FLASH, 8 GiB
  • Implements glue-logic required to be compatible with the CPCI-S.1 R1.0 standard
  • More than 70 % of the FPGA resources are available for user-defined function

Backplane interfaces

  • Dual star network, 8x SpaceWire links with GR740
  • Redundant CAN bus with GR740
  • Full mesh network with High Speed Serial Links (SpaceFibre) with RTG4
  • I2C with RTG4
  • Alarms and other utility signals

Front panel interfaces

  • 2x SpaceWire links
  • Ethernet
  • JTAG debug links
  • 2x Pulse Per Second (PPS) inputs for synchronization
  • GPIO


  • Compressed folders with all the design files are available for
    download at the following links.

    Please check the disclaimer file before downloading the package.
    Contact for the password.

Table of Content for Flight model Reference Data Package

(accessible without password)

Flight model Reference Data Package (Binary files)


(password protected, contact )

Flight model Reference Data Package (PDF files)

(password protected, contact )

GR740-SBC Reference Design Brochure

GRBOOT - Flight Software Boot Loader

  • Developed in accordance with standards ECSS-E-ST-40C, tailored software criticality category B.
  • Provides initialization, self-test and application loading functionality
  • Tailoring functionality to the GR740SBC platform
  • Environment: Mission

Learn more

GRBOOT-STANDBY - Flight Software Boot Maintenance

  • The GRBOOT-STANDY software maintenance mode allows for application uploading and patching and diagnosis.
  • Environment: Mission

Learn more

Test application and EGSE software

  • Developed to verify the board interfaces and memories on a functional level
  • Can be reused and extended for a specific implementation of the GR740 SBC platform simplifying functional verification of the hardware
  • Environment: Terrestrial

RTEMS5-SMP support for the GR740 SBC

  • Peripheral drivers linked with user application