| 摘要 |
PURPOSE:To avoid interference between orders by writing mask information to the first and second registers, reading reference of mask information from the second register and once transcribing the contents to the first and second registers when reference is completed. CONSTITUTION:The first register 10 successively stores mask information 100 and an input to the second register 20 determines input mask information 100 or an output of the first register 10 by means of a selecting circuit 1S controlled by a mask information writing control part 40. When an output and the output of the mask information writing control part 40 are coincident by a reference address generating part 50 outputting a reading address of the second register 20, writing to the second register 20 is prohibited. The mask information writing control part 40 is controlled by a mask reference completion indication signal 620 and the selecting circuit 1S selects the output of the first register 10. |
