What you learn today
- Collect and weight alarms
- Acknowledge
- History
When everything beeps at once, nobody listens any more. An alarm centre collects the base's alarms, decides which ones get loud and remembers what happened. You know the tool for it from bit week.
Collecting alarms
Every alarm gets a bit in one single register:
| Bit | Alarm | Weight |
|---|---|---|
| 0 | oxygen below 18 % | danger |
| 1 | pressure below 80 kPa | danger |
| 2 | temperature above 40 °C | warning |
| 3 | sensor missing | danger |
If the sensor is missing, all comparisons are 0. Bit 3 makes sure it is noticed anyway – a silent sensor is an alarm in itself.
Weighting
Danger means: klaxon and light. Warning means: light only. A mask decides which bits are dangerous: %1011 are bits 0, 1 and 3. Whoever wants to reclassify an alarm later only changes the define.
Acknowledging
An alarm is only done once a person has seen it. That is why the klaxon does not run while an alarm is active, but while it is unacknowledged. The chip finds new alarms with the same edge detection as in the flag register:
not tmp alt
and new active tmp # active now and not before
move alt active
or pending pending new # pending until acknowledged
and tmp pending GEFAHR # only dangerous bits soundPressing “Quittung” clears the pending alarms. The klaxon goes quiet, the flashing light stays on until the cause is really fixed. If a new alarm comes after that, it sounds again.
History
A counter counts every alarm event, a Logic Memory keeps the last new alarm as a bit pattern. Whoever comes into the base after a night sees that something happened and what – even if everything has long been green again.
Acknowledging fixes nothing. A chip that also switches off the flashing light after acknowledging hides a running fault.
Diagram
Exercise
Task
Build the alarm centre according to the table above. Sensor “Basis”, display “Alarmcode” (active bits), klaxon “Alarm” (on while a dangerous alarm is unacknowledged), flashing light “Alarm” (on while any alarm is active), button “Quittung”, display “Alarmzahl” (number of alarm events) and Logic Memory “Letzter_Alarm” (bits of the last new alarm).
Hints
Hint 1
Bits with slt/sgt and ins active tmp N 1, bit 3 with snan tmp p.
Hint 2
New: not tmp alt, and new active tmp, move alt active, then or pending pending new.
Hint 3
Klaxon: and tmp pending GEFAHR, snez. Only write the last alarm when new is not 0.
Quiz
4 questions. You pass from 60 % – the server does the grading.
Complete the day
- Passed the simulator exercise
- Passed the quiz with at least 60 %
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