ISIS On Board Computer

Description

The ISIS On Board computer (IOBC) is a flight-proven, 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 for CubeSats, 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.

• 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 mainboard only, 100g with EM daughter board
• Power Consumption: 400mW average

• Processor: 400MHz 32-bit ARM9 processor
• Volatile Memory: 64MB SDRAM
• Code Storage: 1MB NOR Flash
• Critical Data Storage: 512kb FRAM
• Mass Data Storage: 2 x 2GB high reliability SD cards for fail safe data storage (up to 32 GB on request) or 2x any size standard SD cards

• I²C master or slave mode
• SPI master mode up to 8 slaves
• 2x UART (RS232 + RS232 / RS485 / RS422)
• General Purpose Input / Output pins (GPIO)
• ADC: 8 channel, 10-bit
• PWM: 6 channel
• JTAG for programming and debugging
• Dedicated debug LEDs and UART
• USB host and device
• Image sensor interface

Qualification and Acceptance testing

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

Hardware Abstraction Layer Library
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

Example Daughter boards:

ISIS CORE DAUGHTER BOARD

• compatible with ISIS bus
• supported in ISIS Subsystems Library
• provides interfaces to ISIS solar panels (photodiode and temperature sensors)
• provides data interfaces (RS-422 and RS-232)
• provides power interfaces (switchable 3V3 and 5V lines)

GYROSCOPE DAUGHTER BOARD

• includes all ISIS Core daughter board functionalities and interfaces
• includes low-power MEMS gyro

MAGNETIC CONTROL DAUGHTER BOARD

• includes all ISIS Core daughter board functionalities and interfaces
• includes 3-axis magnetometer
• includes 6 PWM and H-bridges to control magnetorquers

EXAMPLE USE CASES

PEASSS

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

NCLE

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

PicSat

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