Donald L Tietjen: Wait mode power reduction system and method for data processor. Motorola, John A Fisher, Jeffrey Van Myers, Jonathan P Meyer, October 25, 1988: US04780843 (155 worldwide citation)

A method and apparatus for reducing power consumption in a data processing system by interrupting the supply of clocking pulses to selected portions of the system in response to a power-down signal provided by a data processing portion of the system only if the state of a respective control signal i ...


Donald L Tietjen, Michael W Cruess: Method and apparatus for interfacing buses of different sizes. Motorola, John A Fisher, Jeffrey Van Myers, July 28, 1987: US04683534 (79 worldwide citation)

In a data processing system having a first bus sized to accomodate 2.sup.x units of data and a second bus sized to accomodate 2.sup.y units of data, where x and y are positive integers and y is less than or equal to x, a method and apparatus for determining y from the x least significant bits of a c ...

Donald L Tietjen, David M Menard: System and method for avoiding bus contention on a multiplexed bus by providing a time period subsequent to a read operation. Motorola, February 16, 1999: US05872992 (31 worldwide citation)

A bus interface unit within a processor ensures a delay period after the occurrence of a read operation to avoid bus contention on a multiplexed bus, When there is a requirement for a back-to-back read or write operation subsequent to the read bus cycle on a multiplexed bus it is important to allow ...


Pern Shaw, Donald L Tietjen, Michael F Wiles: Programmable mode select by reset. February 14, 1984: US04432049 (19 worldwide citation)

A mode selection circuit is disclosed which is suitable for configuring a data processor at the time at which the data processor is initialized with a reset signal. Mode selection latches are coupled to terminals normally used as an input/output port for the data processor and the latches are clocke ...

Donald L Tietjen, Frank C Galloway, Juan Guillermo Revilla, Nancy G Woodbridge, David M Menard, Ronny L Arnold: Method and apparatus for bursting operand transfers during dynamic bus sizing. Motorola, November 18, 1997: US05689659 (16 worldwide citation)

A data processing system (10) having a bus controller (5) that uses a communication bus (22) which adapts to various system resources (7) and is capable of burst transfers. In one embodiment, the processor core (2) and system resources (7) supply control signals supplying required parameters of the ...

Michael Cruess, Donald L Tietjen, Van B Shahan, Stanley E Groves: Method and apparatus for selectively delaying an interrupt of a coprocessor. Motorola, John A Fisher, Jeffrey Van Myers, July 19, 1988: US04758950 (15 worldwide citation)

A system for interfacing a Processor to a Coprocessor using standard bus cycles. The Processor, upon encountering in its instruction stream an instruction having a particular Operation word format, will transfer a Command word following the Operation word to a particular Coprocessor designated by a ...


Donald L Tietjen, Frank C Galloway, David M Menard, Ronny L Arnold, Nancy G Woodbridge: Method and apparatus for address extension across a multiplexed communication bus. Motorola, July 15, 1997: US05649125 (13 worldwide citation)

A data processing system (10) having a bus controller (5) and a multiplexed communication bus (22) and provides a portion of the valid address information during the data phase. In one embodiment, in response to an address extension control signal, the bus controller (5) allocates the communication ...