PSAS/ SoftwareRequirementsJune2003

Software Requirements, June 2003 Launch

  1. Flight Computer
    1. will initialize with a "power on self test" that determines which CAN nodes are currently active in the system, then enter a valid state in the state machine
    2. will have a manual override to exit the launch-ready state
    3. will accept all CAN packets with < 5% dropped
    4. each CAN packet will take <1 millisecond from receipt at the CAN chip, dispatch by muxer, to signal of action thread
  2. Logger
    1. will have no discernable impact on other processing
    2. will guarantee 100% logging of all packets, including those with failed header checksum, up to the limit of the log buffer
    3. will deal gracefully with log buffer overflow; if necessary, will discard oldest data first
  3. 2.4 Ghz downlink
    1. software will tolerate 100% failure of link
    2. when resuming from a failure, will process most recent data first
    3. will process 10 ping packets per second from the ground to Flight Computer
  4. Assumptions
    1. maximum of 128K bytes/sec received on CAN bus
    2. lots of spare cycles in the Flight Computer
    3. limiting factor will be bandwidth on the 2.4 Ghz link, which is expected to be 1 Mbit/sec in each direction