| 摘要 |
PURPOSE:To correct automatically a delay by a light pen, by setting a scanning line containing a point stored at the time of scanning of the following time, to high luminance, and measuring the time required for obtaining an input from the light pen. CONSTITUTION:A CRT control device 9 sets a present scanning address to a register, sets the whole of one scanning line containing its address to high luminance at the time of the following scanning, and also outputs a start signal to a measuring counter 10. Subsequently, when a light pen detects a high luminance scanning line and a light pen input signal 1 turns on again, a stop signal 4 of the counter 10 turns on by an FF6 and an AND circuit 8. When this signal 4 is inputted, a measured time is set to the register, and a light pen interrupting signal 5 turns on. Accordingly, position information containing a delay by the light pen, and a value of its delay are set to the CRT controlling circuit 9 and the measuring counting circuit 10, respectively. Accordingly, in a software, read of the circuit 10 is subtracted from read of the circuit 9, and a correct position is obtained on the CRT. |
