Abstract: Apparatus for enabling a first processor to cause a second processor to effect a transfer of data between the processors in accordance with data transfer commands sent from the first processor to the second processor is described. The processors each have a program instruction memory for enabling the processors to operate independently and simultaneously when no data transfer is occurring between them, and the apparatus includes data transfer circuitry connected between the processors for enabling the data to be transferred, a program instruction decoder associated with the second processor for normally decoding and executing instructions stored in the program instruction memory of the second processor when no data transfer is occurring, and routing circuitry for carrying the data transfer commands from the first processor to the program instruction decoder for decoding to provide signals to the data transfer circuitry to effect a transfer of data.

Abstract: A two-pass Multiplier/Accumulator Circuit is provided which performs various arithmetic operations on operands contained within an X Register 10 (FIG. 1) and a Y Register 20 and places the result in an Accumulator Register 40. The arithmetic operations are carried out by passing the product of the operands successively through an array of adders in the Adder unit 34. Each adder adds an appropriate multiple of the contents of the X Register to the Accumulator 40 or to the output of the previous adder. The multiples are selected according to the contents of the Y Register.The X and Y Registers are fully buffered so that additional data transfers and functions may be performed while an arithmetic operation is in progress in a "pipeline" manner.The circuit is also capable of indicating the maximum or minimum value in a sequence of numbers in response to a single computer instruction to the circuit.

Abstract: A data processor having an internal address bus and a separate internal data bus which are selectively coupled to an external memory bus. The external memory bus is time shared so that it can carry memory addresses as well as data. A command shift register, at least one capture register, a timer register, a compare register, a control register, and a status register are all coupled to the internal data bus. The command shift register is capable of serially shifting data, upon command, to an output terminal. The at least one capture register is capable of being loaded from the timer register whenever a transition occurs on a predetermined input to the data processor thereby capturing the time at which the transition occurred. The compare register is used to store a digital signal equivalent to some desired time. The compare register is continuously compared for equality with the timer register and provides a signal when equality exists.

Abstract: A microprocessor having separate bidirectional instruction and data busses is disclosed which allows the fetching of instructions from a program memory to be overlapped with the execution of instructions previously fetched. Program instructions are stored in an internal read-only-memory and/or in an external read-only-memory. Variable data is stored in an internal register array. During a given machine cycle, a data word in the register array can be transferred to an arithmetic-logic unit by a bidirectional data bus. The result of the operation performed by the arithmetic-logic unit can be transferred by the data bus back to the register array and stored in the selected location during the same machine cycle. Simultaneously, the contents of a program counter are transferred by a bidirectional instruction memory bus to the program memory to access the instruction to be executed on the following machine cycle.

Abstract: A microprocessor having the capability of performing either a multiply or divide operation from a single instruction for each operation is provided. Much of the standard circuitry of a microprocessor is used along with a multiply/divide cycle counter, logic circuitry, and a shift network separate from the arithmetic logic unit. The microprocessor has the capability of performing unsigned integer multiplication and division. A shift and add algorithm is used for multiplication while for division a non-restoring divide algorithm is used.

Abstract: A microprocessor is disclosed which includes a timer and one or more capture registers. The timer is a counter which is incremented continuously at a fixed clock rate for providing a real time reference. Each capture register is loaded directly from the timer output when a triggering signal appears on a specific input pin, thus recording the time of the occurrence of the triggering signal without interrupt or software intervention.