The PCI configuration address register, also known as the Configuration Address (CA) register or simply Configuration register, is a specific register in the component hardware of a computer system that is utilized by the Peripheral Component Interconnect (PCI) bus to manage and access configuration settings for PCI devices connected to the system.
This register serves as a communication interface between the processor and the PCI bus, allowing the system software to identify, configure, and access various PCI devices such as network cards, sound cards, and graphic cards.
The PCI configuration address register is typically a 32-bit register divided into two fields: the address field and the enable bit field. The address field specifies the PCI device and function to be accessed, with the device number occupying bits 11 to 16 and the function number occupying bits 8 to 10. The enable bit field, often referred to as the Configuration Space Enable (CSE) bit, enables or disables access to the PCI configuration space.
By reading from or writing to the PCI configuration address register, the system software can retrieve information about a specific PCI device, modify its configuration settings, or even initiate certain functions on the device. Each PCI device has its own configuration space, which contains standardized registers that provide vital information about the device's capabilities and characteristics.
In summary, the PCI configuration address register is a crucial component of the PCI bus, enabling system software to communicate with and manage the configuration settings of PCI devices connected to the computer system.
