| 摘要 |
PURPOSE:To easily detect a defective part, by fetching a data content in a register by a scan out circuit at the time of detecting abnormality, supplying it to a microprocessor, and comparing it with the data content obtained at time of writing. CONSTITUTION:The microprocessor 1 is connected to a data bus 3 through registers 2a..., and to the scan out circuit 7 through a scan data bus 12, respectively, and the circuit 7 is connected to the registers 2a... through a shift bus, a shift mode, and a shift clock signal lines 9, 11, and 8. And when no coincidence between data at time of writing and reading, is obtained, the circuit 7 is started up, and the circuit 7 fetches the data of the same number of bits as all of the bits of the registers 2a..., and the processor 1 fetches, for example, the data of the register 2a, and compares it with the data at time of writing. Next when the coincidence between them is obtained, the abnormality of the register 2a, and that of scan data, are displayed, and when they are not equal, the abnormality of them are displayed. |
