TS-7680 LEDs

From Technologic Systems Manuals

On all of our SBCs we include 2 indicator LEDs which are under software control. You can manipulate these using the linux GPIO interface. The LEDs have 4 behaviors from default software.

Green Behavior Red behavior Meaning
Solid On Off System is booted and running
Solid On On for approximately 20s, then off The red LED will remain on from power on until Debian has finished booting. The first boot of the unit will have the LED on longer as part of this process is generating SSH keys for the unit.
On for 10s, off for 100ms, and repeating On for 10s, off for 100ms, and repeating The watchdog is continuously resetting the board. This happens when the system cannot find a valid boot device, or the watchdog is otherwise not being fed. This is normally fed by the kernel once a valid boot media has started. See the #Watchdog section for more details.
Off Off The SBC is not able to boot. Typically either the board is not being supplied with enough voltage, or the SBC has been otherwise damaged. If a stable voltage is being provided and the supply is capable of providing at least 1A to the SBC, an RMA is suggested.
Blinking about 5ms on, about 10ms off. Blinking about 5ms on, about 10ms off. The board is receiving too little power, or something is drawing too much current from the unit's power rails.

Linux GPIO LED control:

Red# 7
Green# 5
Yellow# 58
Blue 56