I'm not sure if the operation on the C32 is any different from the SRT6, but from what I've learned while owning my car, the supercharger operates like this:

The S/C will engage immediately upon acceleration (even below 1,000 RPM) unless the accelerator is gradually pushed. However, even under gradual acceleration, the S/C will still engage by default at 2,900 RPM to prevent damage to the belt and related components from sudden engagement at higher RPM's. This way, if more acceleration is needed, the supercharger will already be locked in and ready to go. If for some reason the supercharger disengages above 2,900 RPM (usually happens due to traction control or ECU going into limp mode) it will not reengage until RPM's drop back below 2,900 RPM.

Another thing to note is that the S/C briefly disengages between shifts. One explanation I've read is that it reduces drive line shock by momentarily reducing power between shifts, but I've also read that this has something to do with the fact that our S/C has no bypass valve. Luckily, because it only disengages momentarily during shifts, the S/C WILL reengage even above 2,900 RPM.