| 摘要 |
PURPOSE:To temporarily stop the action of reading/writing information by detecting that the microprocessor of a control circuit does not operate normally. CONSTITUTION:The writing/reading of information is executed for a memory device selected by a main processor 1, and in parallel with it, an information- writing signal from the main processor 1 or an information-reading signal to the main processor is inputted to a pattern string generating circuit 12. In a pattern string comparison circuit 13, a pattern string outputted from the pattern string generating circuit 12 and a selecting signal to select a memory device outputted by a selection circuit 4 are compared with each other, to detect if there is any difference in the variation order between the two signals. If a difference occurs, it is considered that the microprocessor 5 to control the action of the selection circuit 4 is in an abnormal state, therefore, the pattern string comparison circuit 13 supplies a signal to an emergency stop circuit 14, and the circuit 14 transmits a prescribed signal to the main processor 1 and the control circuit 2 so that the action of writing/reading information is stopped. |
