i assume cpu has direct access to motherboard's BIOS and RAM.(correct me if i'm wrong)
But how does cpu communicate with other hardware like hdds, expansion cards, peripherals, other BIOSes etc.?
I know about OS and its drivers, but they are software- they're in RAM. How does cpu communicate with all this hardware on hardware level? Isn't it limited to only motherboard's BIOS and RAM?
Please correct me if I am wrong. Basically peripheral device communicate with processor using PCI(peripheral component interconnect), it a type of bus that connect the device directly to the processor. when a command is given through a peripheral device (say any button press on keyboard) it is converted into binary code and stored in memory in the form of cache memory and then required execution for that particular function is done by the processor.
