Pci bus with reduced number of signals

Abstract

A Mini-PCI (MPCI) interface, and associated circuits and methods are provided for connecting a Peripheral Component Interconnect (PCI) device to one or more external devices. The MPCI interface, circuits and methods provide for a substantial if not full implementation of a PCI Local Bus without requiring the standard number of pins, traces, or signals. The MPCI interface includes a PCI/MPCI bridge connected between a PCI bus and to up to eight external devices in the form of MPCI devices and linear memory devices. The PCI/MPCI bridge is capable of receiving an incoming PCI transaction and multiplexing some of its signals together to create a corresponding incoming MPCI transaction. This incoming MPCI transaction may then be passed over an MPCI bus, having fewer lines and optimally operating at a higher frequency, the external devices. The process is reversed for outgoing transactions, i.e., the MPCI transactions are de-multiplexed to create PCI transactions. Additionally, the MPCI interface may also be configured to provide for direct access to linearly addressed memory devices without adding a PCI interface to the external interface. The invention may be implemented through integrated circuitry and/or computer implemented instructions, and may be included within a personal computer.