Chapter 2
25
B75H2-M3 USER MANUAL
Hard Drive Activity LED
Connecting pins 1 and 3 to a front panel mounted LED provides visual indication that
data is being read from or written to the hard drive. For the LED to function properly,
an IDE drive should be connected to the onboard IDE interface. The LED will also
show activity for devices connected to the SCSI (hard drive activity LED) connector.
Power/Sleep/Message waiting LED
Connecting pins 2 and 4 to a single or dual-color, front panel mounted LED provides
power on/off, sleep, and message waiting indication.
Reset Switch
Supporting the reset function requires connecting pin 5 and 7 to a momentary-con-
tact switch that is normally open. When the switch is closed, the board resets and
runs POST.
Power Switch
Supporting the power on/off function requires connecting pins 6 and 8 to a momen-
tary-contact switch that is normally open. The switch should maintain contact for at
least 50 ms to signal the power supply to switch on or off. The time requirement is
due to internal de-bounce circuitry. After receiving a power on/off signal, at least
two seconds elapses before the power supply recognizes another on/off signal.
4. Front Panel Header
The front panel header (F_PANEL) provides a standard set of switch and LED headers
commonly found on ATX or Micro ATX cases. Refer to the table below for information:
