Motherboard Description
1.12.1.1SW_ON
This 2-pin header connects to a front panel power switch. When the switch is closed, the power supply turns on. If a mechanical switch is connected to this header, it must apply a momentary ground to the SW_ON header pin in order to signal the supply to turn on or off. Because of the motherboard’s internal debounce circuitry, the ground must be applied for at least 50ms. At least two seconds must pass before the power supply will recognize another on/off signal (to prevent “double clicking”).
1.12.1.2Sleep/Resume
When Advanced Power Management (APM) is activated in the BIOS and the Operating System’s APM driver is loaded, Sleep mode (Standby) can be entered in one of three ways:
∙An optional front panel “Sleep/Resume” button
∙A user defined keyboard hot key
∙Prolonged computer inactivity
The Sleep/Resume button is supported by a 2-pin header located on the front panel I/O connector. Closing the “Sleep” switch generates an SMI (System Management Interrupt) to the processor which immediately goes into System Management Mode (SMM).
The front panel “Sleep mode” switch must be a momentary two pin SPST type that is normally open. The function of the Sleep/Resume button can also be achieved by using a keyboard hot-key sequence, or by a time-out of the inactivity timer. Both the keyboard hot key and the inactivity timer are programmable in the BIOS Setup (timer is set to 10 minutes by default). To reactivate the computer, or “Resume”, the user must simply press the sleep/resume button again, or use the keyboard or PS/2 mouse. Mouse activity only “wakes up” the computer if a mouse driver is loaded. While the computer is in Standby or “sleep” mode, it is fully capable of responding to and servicing external interrupts (such as in-coming FAX) even though the monitor only turns on if a user interrupt (keyboard/mouse) occurs as mentioned above.
1.12.1.3Infrared Connector
Serial port 2 can be configured to support an IrDA module with a 5 pin header connector. Once configured for IrDA, the user can transfer files to or from portable devices such as laptops, PDAs and printers using application software such as LapLink. The IrDA specification provides for data transfers at 115 Kbps from a distance of 1 meter. Consumer IR is also supported by the same connector.
1.12.1.4Hard Drive LED
This 3-pin, keyed header can be connected to a front panel LED to indicate when hard drive activity is taking place. When the hard drive is being accessed, the HDACTIVE pin (J2A1-15) goes low.
1.12.1.5Power-ON LED
This 2-pin header can be connected to a front panel LED to indicate when power is applied to the motherboard. When the motherboard is powered up, power is applied to the PWRDRV pin (J2A1-20) to light the front panel LED.
