What are the pci commands?

PCI commands are instructions used in the Peripheral Component Interconnect (PCI) protocol to manage and control devices connected to the PCI bus. These commands include configuration space access commands, such as reading and writing configuration registers, as well as memory and I/O operations for data transfer. Common PCI commands include Memory Read, Memory Write, I/O Read, and I/O Write. These commands facilitate communication between the CPU and peripheral devices, enabling efficient data handling and device management.