Patent ID: 6301632
Filing Date: 2001-10-09
Classification: G06F

Abstract:
A PCI to SH4 direct access bridge providing translation between PCI bus protocol messages and SH4 microprocessor bus protocol messages comprising:a PCI interface component compliant with said PCI bus protocol, said PCI interface component adapted to receive and transmit data and fundamental message information to and from a PCI bus, anda SH4 interface compliant with said SH4 microprocessor bus protocol and coupled to said PCI interface, said SH4 interface adapted to receive and transmit said data and fundamental transfer information to and from a SH4 microprocessor demand data transfer (DDT) protocol bus, wherein said SH4 interface component includes:a first state machine adapted to initiate control commands for components of said SH4 interface component and form DDT requests;a DDT counter coupled to said second state machine, said DDT counter is adapted to assist said second state machine determine counts required to perform DDT requests and transfers;a MUX coupled to said second state machine, said MUX is adapted to pass fundamental message information or data associated with a DDT request onto said SH4 microprocessor internal bus; anda plurality of control registers, said plurality of control registers being adapted to satisfy timing requirements and control constraints.