General attributes of command processors

• Each command packet has a time tag associated with it

  • Absolute execution time (in units of spacecraft clock ticks to one second accuracy)
  • Delta time after previous command (in units of 1 second)
  • A few commands implicitly have delta time tags of 0 seconds (immediate execution)

• Each command processor maintains a pointer to the next command to be executed

  • Execution time is computed based on type of time tag
  • Execution time is in units of one second
  • Processor can be idled by setting address pointer to 0

• Executive cycles through each of the processors each 40 Hz. cycle and checks if the current time matches the execution time

  • If so, executes command by sending to appropriate hardware or software destination
  • Moves pointer down to the next command and computes its execution time

• Command pointer for each processor can be moved by command in another processor or by the flight software itself

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