ISIS On Board Computer

Flight Heritage since 2014


The ISIS on board computer (IOBC) is a flight qualified, high-performance processing unit based around an ARM9 processor with a speed of 400 MHz, making it one of the most capable on-board computers currently available on the market within the same price range. Its pluggable daughter board offers additional flexibility and customizability by providing a wide range of extra interfaces for payloads, sensors or actuators in a compact form factor.

Availability: 8 – 12 weeks

  • Features
  • Product properties
  • Performance
  • Configurations
  • Qualification and acceptance testing
  • Daughter Boards
  • Documents/CAD


  • JTAG programmer
  • 400 MHz, power efficient ARM9 processor
  • Free RTOS operating system for simple and lightweight cooperative multitasking
  • Data Storage:
    • Redundant SD Card storage 2x2GB (other sizes are available on request) with FailSafe FAT journaling file system
    • 256kB FRAM: reliable Non-Volatile Storage
  • 2x redundant Real Time Clock
  • On-board temperature sensor
  • External on-board watchdog and power-controller
  • Robust design
  • Includes Hardware Abstraction Layer software
    This library supports the following peripherals:

    • I2C master mode
    • I2C slave mode
    • Pulse Width Modulation (PWM)
    • UART (RS232, RS422, RS485)
    • SPI master mode
    • FRAM read and write
    • SD card using failsafe FAT journalling filesystem
    • Real-Time Clock (RTC) and OBC internal timer (RTT)
    • Debug LED control

    This library offers the following additional functionality:

    • Checksumming (CRC-8, CRC-16, CRC-32)
    • Interface to iOBC Supervisor
    • Watchdog kicking
    • Timekeeping
    • FreeRTOS operating system
    • AT91 library from Atmel
  • Compatible with standard CubeSat components available from ISIS
  • Compatible with Gomspace EPS
  • Compliant with CubeSat standard

Product properties

  • Operating Temperature: -25 degC to +65 degC
  • Power Supply: 3.3V
  • Dimension: 96 x 90 x 12.4 [mm] (including FM daughter board)
  • Mass: 94g (including FM daughter board)


  • Processor: 400MHz 32-bit ARM9 processor
  • Volatile Memory: 64MB RAM
  • Data Storage: 2x 2GB (high reliability SD cards) or 2x any size standard SD cards
  • Code Storage: 1MB NOR Flash
  • FRAM: 256KB
  • Power Consumption: 400mW average (550 mW max @3.3V)
  • Interface
    • I2C (master or slave, up to 400 kbits/s on fast mode)
    • SPI: up to 8 slaves, up to 10 Mbit/s
    • UART: 2x RS232 or 1x RS232 + 1x RS485/RS422
    • ADC: 8 channel, 10-bit
    • PWM: 6 channel
    • GPIO: up to 27
    • 1x USB host
    • 1x USB device
    • Image Sensor Interface for directly interfacing CMOS Image Sensors
    • JTAG for programming
    • Debug port: UART for console user-interface
    • 4x LEDs (Engineering Model only) to support testing and debugging

Available configurations

Main board with:

  • EM daughter board
    • Provides easy access to all interfaces for development and debugging
  • FM daughter board
    • All interfaces in compact form factor
    • High reliability connectors for flight
  • Custom daughter board
    • Design your own daughterboard with additional interfacing and electronics based on mission requirements
  • No daughter board

Additional Software on demand:

Qualification and Acceptance testing

Test QT AT
Mechanical Shock
Thermal Cycling
Thermal Vacuum

*QT is performed on the design/qualification model
*AT is performed on the unit to be shipped

  • compatible with ISIS bus
  • supported in ISIS Subsystems Library
  • provides interfaces to ISIS solar panels (photodiode and temperature sensors)
  • provides data interfaces (RS-422 or RS-232)
  • provides power interfaces (switchable 3V3 and 5V lines)
  • includes all ISIS Core daughter board functionalities and interfaces
  • includes low-power MEMS gyro
  • includes all ISIS Core daughter board functionalities and interfaces
  • includes 3-axis magnetometer
  • includes 6 PWM and H-bridges to control magnetorquers


  • provides various payload control signals and interfaces while performing simultaneous data acquisition for several payloads


  • provides hot redundant CAN interface and solid state recorder data output to Chang’e-4 relay satellite currently at the Earth-Moon L2 point


  • provides power and data interfaces to the payload and ADCS subsystems