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Chapter 4: Motherboard Connections
UID (Unit Idenfication)/BMC Reset Switch and UID/BMC Reset LED Indicators
A UID LED/BMC Reset switch (JUIDB1) is located on the rear side of the motherboard. This
switch has dual functions. It can be used to identify a system unit that is in need of service,
and it can also be used to reset the BMC settings.
When functioning as a UID LED switch, it can turn the UID LED (UID_LED1) on and off to
identify a unit that may require service.
When functioning as a BMC reset switch and working in conjunction with BMC Heartbeat LED
(LED2), JUIDB1 will trigger a cold reboot when the user presses and holds the switch for 6
seconds. It will also restore the BMC to the manufacturer's default when the user presses
and holds the switch for 12 seconds.
To achieve these dual purposes, the UID LED/BMC Reset switch works in conjunction with the
BMC Heartbeat LED (LED2). Refer to the tables below for more details. Please note that UID
can also be triggered via BMC on the motherboard. Refer to the BMC User's Guide posted
on our website at
http://www.supermicro.com
for more information on BMC.
UID/BMC Reset Switch (JUIDB1) Features & Settings
When Used as a UID LED Switch
(works with UID_LED1)
When Used as a BMC Reset Switch
(works with BMC Heartbeat LED (LED2))
Color
Status
BMC Heartbeat LED
LED2
Green Blinking: BMC Normal
Blue: On
Unit Identified
BMC Reset: Press & hold the
switch (JUIDB1) for 6 seconds
LED2: Solid green: during reboot
Press the switch (JUIDB1) to turn on
and off the UID LED.
Triggering a cold reboot; LED: solid green on
during cold reboot
BMC Reset: Press & hold the
switch (JUIDB1) for 12 seconds
LED2: Solid green: during BMC reset
BMC: Reset to the manufacturer's default;
LED: solid green on during BMC Reset
UID/BMC Reset Switch (JUIDB1)
Pin Definitions
Pin#
Definition
1
Ground
2
Ground
3
Button In
4
Button In