| 摘要 |
<p>PURPOSE:To simplify the constitution by eliminating a lower face start address register, taking a timing by a synchronizing signal and inputting the output data of an upper face display address counter to a lower face horizontal start address latch. CONSTITUTION:A synchronizing signal generator 12 outputs synchronizing signals 121-126 by synchronizing with a fundamental clock 111, data 131 of an upper face start address register 13 is latched to an upper face horizontal start address latch 14, and also, output data 141 of the latch 14 is inputted to an upper face display address counter 15. Subsequently, when the synchronizing signal 126 is in a low level, an output 151 of the counter 15 is synchronized with a rise of the synchronizing signal 125 and latched to a lower face horizontal start address latch 17. Moreover, output data 171 of the latch 17 is outputted to a lower face display address counter 18 and displayed. In such a way, a lower face start address register becomes unnecessary, and the constitution can be simplified.</p> |
