Importance

Loading Importance Indicators...

Abstract

A microcomputer includes a maskable interrupt request terminal, a maskable interrupt request terminal, and a nonmaskable interrupt request terminal, and internally contains a status register having a group of flags indicating a maskable interrupt allowing level, a flag indicating that a nonmaskable interrupt processing is under execution, a flag indicating that an exception processing is under execution, and a flag indicating inhibition of the maskable interrupt. There are also internally provided first and second save registers for saving the content of the status register and the content of a program counter, respectively, when the maskable interrupt request is acknowledged, and third and fourth save registers for saving the content of the status register and the content of a program counter, respectively, when the nonmaskable interrupt request is acknowledged. A register is provided to independently indicate the acknowledgement of the maskable interrupt and the acknowledgement of the nonmaskable interrupt, and a comparator compares the level designated by the maskable interrupt allowing level indicating flag group with an interrupt request level notified through the maskable interrupt request level terminal.

Loading the Abstract Image...

First Claim