| 摘要 |
PURPOSE:To execute easily a pattern registration for satisfying a periodical boundary condition by providing a pattern registration memory for registering a prescribed pattern, and an address generating circuit for generating an address for reading out a pattern in an optional period, between a picture drawing circuit and a CPU. CONSTITUTION:A CPU1 inputs a write pattern data to a memory 4, and also registers an effective period in a registration pattern. In accordance with a pattern write request from the CPU1, a timing controlling circuit 7 registers a pattern through an address switching circuit 5 by a prescribed timing. Also, by an instruction from the CPU1, a picture drawing circuit sends out a pattern read-out request to the timing controlling circuit 7. By a read-out timing from the timing controlling circuit 7, repeat periods of a read-out address counter 81 and a comparator 82 of a read-out address generating circuit 8 are compared and a read-out address is generated. A pattern data from the memory 4 is inputted to the picture drawing circuit. |
