| 摘要 |
PURPOSE:To inform plural interruption factors to a CPU by using one interruption line, and to realize a function which is equivalent to having plural interruption lines, by constituting a title circuit so that a kind of the interruption is encoded and informed to the CPU. CONSTITUTION:In plural interruption factors, in case when only an interruption factor signal 2 is inputted to an interruption generating circuit 10, and interruption discriminating signal 16 which passes through an encoder 18 is encoded as '1000', becomes '8', and sent to a peripheral port (PPI)9. On the other hand, the interruption factor signal 12 sets a flip-flop 7 through a multi-input NOR circuit 17, and interrupting signal 2 is sent to a CPU8. The CPU8 reads the interruption discriminating signal 16 which is inputted to the PPI9, through a line 6 in order to detect by which one of four interruption factors the interruption is executed, and since it is '8', the interruption factor signal 12 is discriminated.
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