| 摘要 |
<p>PURPOSE:To make it possible to transfer coordinate data directly to a host computer to adopt a polling system by using a one-chip CPU incorporated in the tablet. CONSTITUTION:The tablet can be connected to the host computer 5 through a two-way parallel bus, and transfers the coordinate data expressed by a duty ratio binarized pulse train by exchanging a processing unit at any time in conformity to a polling system. A one-chip CPU 14 is provided with a synchronous type serial port 16 capable of being connected directly to the two-way parallel bus in addition to a tablet processing part 15. Further, it is provided with a timer counter T1 for setting the period of the synchronizing signal of the serial port 16. Besides, it is provided with a one-shot timer T3 for activating the serial port 16 in response to the arrival of the processing unit through the parallel bus, and enabling transmission and reception.</p> |
