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Modes description

Initialization mode (when EPS is booted)

Systems powered: EPS

1. Actions in this mode:

• The burn wire is checked and if it has not been burned yet EPS waits xx seconds,

burns the wire else the mode is changed to safe. After a burn the wire is rechecked and if it's burned changes mode to Safe. If the burn did not succeed the burn is retried until burned or max x retries before changing state to safe mode.

2. Responsibility for mode change:

• EPS can change the mode to Safe.

3. Mode change requeriments:

• Jump to Safe mode when the burn wire has been checked.
• Jump to Safe mode after max number of burn retries.

Safe mode

Systems powered: EPS

1. Actions in this mode:

• Battery is charged/conditioned.

2. Responsibility for mode change:

• EPS can change the mode to Recovery.

3. Mode change requeriments:

• Jump to Recovery mode when battery voltage is high enough and temperature is ok?

Recovery mode

Systems powered: EPS, COM, OBC

1.Actions in this mode:

• COM is being booted and starts in basic beacon mode. Bat. voltage is recieved from EPS.
• OBC is being booted. On boot failure use an exponential backing alorithm (boot retry frequncy drops with time) to retry OBC boot.

2. Responsibility for mode change:

• EPS can change the mode to Safe.
• CDH can change the mode to Nominal.

3. Mode change requeriments:

• Jump to Nominal mode when OBC has booted succesfully.
• Jump to Safe mode when battery voltage to low.

4. Mode change actions (to nominal mode)

• CDH sends boot-ok to EPS
• On Boot-ok EPS starts WD.timer
• CDH sends nominal mode beacon
• On data from OBC COM changes mode to Nominal.

Nominal mode

Systems powered: EPS, COM, OBC, (ADCS, P/L)

1. Actions in this mode:

• CDH waits for commands from ground
• CDH sends nominal mode beacon

2. Responsibility for mode change:

• EPS can change the mode to Recovery
• EPS can change the mode to Safe.
• CDH can change the mode to Initialization
• CDH can change the mode to Recovery

3. Mode change requeriments:

• Jump to Recovery mode on WDT Timeout (EPS) or when CDH decides to reboot (Command from CDH).
• Jump to Safe mode when temperature of ?? is critical, or battery voltage is low.
• Jump to Initialization mode when CDH decides to do a hard reboot.

Init sequence for subsytems

• CDH sends command to EPS requesting power for a subsytem.
• Confirmation from EPS.
• CDH starts subsystem thread.

Shutdown scenarios for subsystems

1. EPS hardlimit is reached => imidiate shutdown.

2. CDH monitors power levels / temperature and shuts subsystems down nicely before EPS hard shutdown is necessary.

• CDH sends shutdown message to subsystem
• CDH waits for reply or times out
• CDH send SS-shutdown command to EPS
• EPS sends confirmation?