| 摘要 |
PURPOSE:To easily discriminate an error in fetching by adding a one-bit signal to output data of a specific address. CONSTITUTION:An address signal 2 from a digital differential analyzer DDA is decoded by a decoder 5 and if there is an address to be outputted, a gate 3 is opened by a decoding output 4 to store the output data 1 of the DDA in a buffer memory 7. In this case, while the gate 3 is opened for data on a specific address, connection with the memory 7 is made to store the data in the memory 7 together with an added one-bit signal. A CPU8 fetches data from the memory 7 one after another, but the range of data fetched at a time is made clear by finding the specific bit in the data, so that an error in fetching even if occurs is discriminated easily. |
