PCI,
Continued
Buffered Reads and Writes The PCI Controller buffers reads and writes between the memory/CPU and PCI peripheral
devices.
PCI Component Classes
PCI components must be one of three classes: bus master, slave, or master/slave combination.
Bus Mastering
PCI devices can be bus masters, slaves, or a combination of bus master and slave.
Concurrent Operation
The CPU in a PCI system runs concurrently with PCI bus mastering peripherals.
Although bus mastering peripheral devices are arbitrated, significant data transfer rate improvements can be
achieved without splitting resource utilization between the CPU and a bus mastering device.
Peripheral devices can operate at speeds up to 33 MHz in a PCI environment.
Burst Mode
The PCI specification also provides for burst mode of any length for both reads and writes.
Multiplexing
PCI is a multiplexed bus. Multiplexing allows more than one signal to be sent on the same electrical path.
The control mechanisms have been modified and extended to optimize I/O support.
PCI Adapter Cards The Apollo Pentium PCI Pentium motherboard has four PCI expansion slots. The PCI expansion slots can
accept any adapter card that complies with the PCI Revision 2.0 specification.
All PCI expansion slots are bus mastering slots.
Chapter 2 PCI
13