The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 16, 2001
Filed:
Jun. 11, 1997
Shinichi Yamaura, Kobe, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
When an interrupt request signal is input, a microprocessor checks, upon termination of an instruction cycle being executed, whether the interrupt request is masked. If the interrupt request is not masked, the microprocessor saves the content of the program counter and the processor status register to a stack. If an extended interrupt request signal is at a high level, the microprocessor sets the bus status signals to a unique state so that a data bus is in a high impedance state. An interrupt controller outputs mask flag data to the data bus so that the mask flag data is saved to a stack. Thereafter, the three-byte data is fetched from a vector address and stored in the program counter. When the mask flag data is to be restored, the mask flag data is read while the bus status signals are set to the unique state.