Mitsubishi Denki Kabushiki Kaisha

Kohji Kawamoto

Yukihiko Shimazu

Toshiki Fujiyama

A microprocessor with a built-in instruction ROM is described. Arbitrary data is set in advance in a data register of the microprocessor. The arbitrary data is given to a program counter by a register indirect jump instruction. The microprocessor has a normal reset function and an additional reset function allowing reset from a predetermined address. The additional reset function is used when the logic level of a control signal input terminal is at a predetermined level when the reset signal to the reset terminal is cleared. The arbitrary data is transferred to the program counter by register indirect jump instruction and set in the program counter. The program is re-executed with this data as an instruction start address.

Microprocessor with reset execution from an arbitrary address

A microprocessor which, following a reset signal, permits execution beginning from an arbitrary address. The microprocessor is constituted in a manner such that arbitrary data is set in advance in a data register as an address. The address in the data register is given to a program counter by a register indirect jump instruction which does not originate in the instruction ROM. The microprocessor has a resetting function in addition to the normal resetting function. The normal resetting function includes re-executing a program from a predetermined address, such as a zero address. The normal resetting function occurs in the case where the logical level of a control signal input terminal is a predetermined level at a point of time when the reset signal to the reset terminal is cleared. When the control signal is at a different level, the arbitrary data set in the data register is transferred to the program counter by the register indirect jump instruction and is set in the program counter. The program is then re-executed with that data set as an instruction start address.

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Itami, Japan

Kohji Kawamoto