| 摘要 |
PURPOSE:To improve the data processing efficiency by transmitting an interruption signal to a CPU from a detection circuit within a chip when a collation of signals is produced in an external bus and therefore supplying a countermeasure from the CPU to attain the data reprocessing. CONSTITUTION:It is supposed that the collation of signals is produced on an external bus when the potential is set at H at a contact (c), i.e., the external bus is grounded by some reason. In such a case, the potential of the contact (c) drops and the minus side input of a comparator C1 is reduced less than the reference voltage VH. Therefore a signal of an H level is outputted from the comparator C1 and supplied to an AND gate A1. Then an H side collision detecting signal SSH is outputted by the H-level signal of the gate A1 and a signal of an H level sent from a junction (a) and sent to an OR gate 61. Then the gate 6 sends a collision detecting signal SS1 to an OR gate within the same chip, and this OR gate outputs an interruption signal to supply it to a terminal INT of a CPU10. Receiving this interruption signal, the CPU10 knows that the external bus has the collision of signals and processes data again. |
