| 摘要 |
<p>PURPOSE:To obtain a timer controlling circuit constituted of a small quantity of hardware by detecting and holding overflow or underflow from the result of operation of an updating circuit, direction of updating and a count command signal. CONSTITUTION:Counted value of each timer stored in a register file 1 is operated by an adder-subtracter 5 basing on addition and subtraction constant and direction of updating stored in a register file 2 and command of count command signal of each timer held in FF group 4, and stored again in the register file 1. At this time, output of the adder-subtracter 5, that is, overflow or underflow of the result of operation is detected by a detecting circuit 6, and stored in an FF group 7. Accordingly, plural timers can be constituted of a proper updating circuit and only one overflow and underflow detecting circuit.</p> |
