What were the triggers for the many events in Curiosity's descent?

So many extraordinary “events” or stages. The ejections, the two shield drops, the parachute deployment and cut-off, unloading and operation of sky crane.

These were not handled in real-time; some serious algorithms churned away.

What governed their execution? Barometry, temperature, radiation level? Timing? Nukes have many triggering confirmations before going off, as an example.

I’d be surprised if timing played a big part aside from short-term sequencing and error state detection. And almost certainly not barometry (too imprecise, plus the Martian atmosphere is so thin), temperature, or radiation.

I know for certain that cameras, radars, accelerometers, gyroscopes, and pressure sensors all played a part. For instance, the skycrane stopped lowering when the rover’s wheels (or suspension arms) sensed pressure. The distance to the ground was mostly via radar.

Sadly, the JPL website is too generic and not talking about this.