The system controller slot is Slot 1 of the chassis and is a 4-Link configuration system slot as defined by the CompactPCI Express and PXI Express specifications. The chassis includes three system controller expansion slots for system controller modules that are wider than one slot. These slots allow the system controller to expand to the left to prevent the system controller from using peripheral slots.
The backplane routes each of the system slots’ x4 PCI Express links to a PCI Express switch. The four PCI Express switches have x4 PCI Express links routed to each peripheral slot as well as x1 links to two PCI Express-to-PCI bridges providing 32-bit/33 MHz PCI buses to the hybrid slots.
By default, the system controller controls the power supply with the PS_ON# signals. A logic low on this line powers on the power supply.