| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect in real time whether a monitor is connected on a PC main body side, in a monitor interface having no signal line for detecting monitor connection. <P>SOLUTION: Switching means SW1 and SW2 are serially connected to pull-up resistors R11 and R12 on the PC body 1 side of the DDC signal line. When the DDC is in an idle state, the switching means SW1 and SW2 are turned off, and the pull-up signals of the DDC CLK (SCL) and the DDC DATA (SDA) are made disconnected. The electric potential level of the SCL/SDA signal line is detected on the body 1 side; and when this electric potential level is changed, an interrupt signal is generated; and when the interrupt signal is generated, it is determined whether a monitor is connected or disconnected from the direction of the change in the electric potential level of the SCL/SDA signal line on the PC body 1 side. <P>COPYRIGHT: (C)2007,JPO&INPIT |
