| 摘要 |
<p>PURPOSE:To make use of a program counter as a timer with efficiency by actuating the program counter as a timer and then by restoring the contents of a stand-by register in the program counter while removing a prohibition of instruction inputting to an instruction register when the count value of the program counter reaches a fixed value. CONSTITUTION:Once a control instruction permitting the use of program counter 3 as a timer is set in instruction register 4, timer operation is started, FF6 is put into operation to transfer the contents of counter 3 to stand-by register 9, and instruction input gate 8 of register 4 is turned OFF to inhibit the inputting of a new instruction. When the count value of counter 3 reaches a fixed value, the prohibition of instruction inputting to gate 8 is removed and the stand-by contents of register 9 are restored in counter 3. Consequently, counter 3 can efficiently be used as a timer.</p> |
