| 摘要 |
PURPOSE:To read out an ROM data without exerting effect on the operation of a logical circuit, by reading out the state of a data register and a readout end FF after a microprocessor outputs an address of a set read only memory and confirming the content of the set read only memory. CONSTITUTION:The microprocessor 3 transfers readout ROM address designated on an operation display device 14 with the operator to an ROM address register 22. An output 23 of the register 22 and an output 8 of a logical circuit 2 are compared 23 and when both are coincident, a coincidence signal 25 is transmitted to a timing control circuit 26. Further, the circuit 26 outputs a synchronizing signal 27 to store an ROM data outputted on a readout line 11 to an ROM data register 12 and to set a read end FF28. On the other hand, the processor 3 outputs an ROM address to the register 22, then the state of the FF28 and the register 12 is read out via a bus 6 and when the FF28 is set, the content of the register 12 is displayed on an operation display device 14 to complete the readout. |
