| 摘要 |
PURPOSE:To obtain a device easy to perform programming inexpensively by storing the program of fixed length in a patrol type shift register, executing a microinstruction sequentially by taking out from the patrol type shift register, and providing a branch control means. CONSTITUTION:The microprogram of 256 steps is outputted repeatedly at every constant period equivalent to one sampling period by the patrol type shift register consisting of a selector 11 and a microprogram shift register 12. An individual microinstruction is decoded by a program decoder 3, and the microinstruction can be executed. Also, when branch is performed by executing a branch instruction, it can be performed effectively by prohibiting data write on memory, etc., in a period while the count value of a program step counter 31 which performs a count operation synchronizing with the fetch of the microinstruction coincides with a branch destination address. |
