Texas Instruments Corporation

Daniel L Essig

Surendar S Magar

Joe F Sexton

Edward R Caudel

Graham S Tubbs

Luat Q Pham

Richard D Simpson

A data processing system which has an interface circuit that interfaces the data processing system to input devices. The interface includes an input means such as a pad for conducting signal levels from the interface devices to the data processing system. A digitizer, such as a Schmitt trigger, digitizes the signal levels to signal levels that are acceptable by the data processing system. An output line conditioner conditions the data lines that are connected to the digitizers to prevent overdriving of the data lines by the digitizers. Line drivers are used for driving the digitized system on the data lines throughout the data processing system.

Interface circuit for data processing system

A system for real-time digital signal processing employs a single-chip microcomputer device having separate on-chip program and data memory, with separate address and data paths for program and data. An external program address bus allows off-chip program fitch in an expansion mode, with the opcode returned by an external data bus. A bus interchange module allows transfer between the separate internal program and data busses in special circumstances. The internal busses are 16-bit, while the ALU and accumulator are 32-bit. A multiplier circuit produces a single state 16.times.16 multiply function separate from the ALU, 32-bit output to the ALU. One input to the ALU passes through a 0-to-15 bit shifter with sign extension. The on-chip program memory may be a RAM and this additional RAM may be configured as either program or data memory space. The processor may operate with all off-chip program memory and a large on-chip data memory, or with program execution from on-chip RAM (downloaded from off-chip program memory) using a block move instruction. A repeat instruction is used to save program space when using block-move, or multiply instructions as needed for digital filters or the like.

Microprocessor with block move instruction

A system for real-time digital signal processing employs a single-chip microcomputer device having separate on-chip program and data memory, with separate address and data paths for program and data. An external program address bus allows off-chip program fetch in an expansion mode, with the opcode returned by an external data bus. A bus interchange module allows transfer between the separate internal program and data busses in special circumstances. A multiplier circuit produces a single state multiply function separate from the ALU. One input to the ALU passes through a full-width shifter with sign extension. The on-chip program memory is a RAM which may be configured as either program or data memory space. The processor may operate will all off-chip program memory and a large on-chip data memory, or with program execution from on-chip RAM (downloaded from the off-chip program memory) using a block move instruction. A repeat instruction is used to save program space when using block-move, or when using multiply instructions as needed for digital filters or the like.

Microprocessor with repeat instruction

A digital multiplication circuit for a microprocessor utilizes a modified Booth algorithm for implementing the digital multiplication of two numbers and includes a Booth recoder for recoding the multiplier into a selected number, n, of Booth operation sets where n is a positive integer that equals one-half the number of bits in the multiplier. Each operation set is applied to a second plurality of n partial products selectors which are connected in cascade arrangement according to multiplicand sets and wherein each partial product selector multiplicand set implements one of the recoded Booth operation sets. The outputs of the partial product selectors are summed by a summation means and a domino circuit means provides an evaluation pulse for each member of the partial product selector at the completion of the Booth operation set that is connected to the partial product selector.

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Daniel L Essig