The ADL Embedded Solutions SBC’s ADLS15PC, ADLGS45PC, ADLD25PC, ADL2000PC, ADLQM67PC, ADLQM87PC, and ADLE3800PC, employ a power management PIC that monitors and controls the gating of supply power into the SBC. This Power Management PIC includes a status LED that can provide some indication as to the condition of the system power as it pertains to the SBC. The following colors / conditions are defined for specific (and non-specific) board states. The following table describes some of the status LED states:

Status Codes RGB LED:

Color Interval Meaning
none solid Invalid system state
White solid The microcontroller has just been flashed and is being prepared for normal operation after reboot
Cyan solid Reserved
Magenta solid Reserved
Blue solid Reserved
Yellow solid Reserved
Green solid Board operates normal
Red solid Board is in Reset
Green/Yellow flashing Bootloader operates normal
Red flashing Firmware is being started (start sequence still running)
Red/Yellow flashing Bootloader is being started (start sequence still running)
Red/Magenta flashing Checksum error during I2C transmission in bootloader
Red/Blue flashing Update completed, waiting for manual Reset
Yellow flashing (10s) S5 state
Yellow flashing (6s) S4 state
Yellow flashing (3s) Reserved
Yellow flashing (0.5s) Reserved

There may also be variations that are not covered by the table above.

In most cases, any RED LED means that there is an issue with the supply power. The status LED turns RED when the PIC is in RESET.

Reset is caused by the following:

  • Source power has been asserted: PIC will go into reset at first power up to keep unstable power from entering the SBC. Once stable power it detected, it will gate the supply power into the board to allow it to boot.
  • Flashing red: Power has been asserted and the Status LED flashes Red. There is an undervoltage/undercurrent condition that is perhaps caused by an undersized power supply, undersized wire gauge or not all supply power pins are being used.
  • Solid Red: Overvoltage / Overcurrent or catastrophic error in the PIC, possibly due to an abnormal power event.


A yellow LED typically indicates standby or sleep states, however there are also undefined states not covered by the table above. These types of conditions can be caused by abnormal power events can happen infrequently. For the defined YELLOW states above, using the board momentary switch will return the board to normal operation. For the reserved states, or other undefined YELLOW LED conditions, it may be necessary to remove all power from the SBC including the CMOS battery, to clear out any erroneous data inside the PIC.

For any occurrence not described please contact ADL Embedded Solutions Technical Support for more in-depth troubleshooting.