TS-7840 LEDs
From embeddedTS Manuals
The TS-7840 has 6 external status LEDs, one internal blue LED, and control over the link status LEDs on the RJ45.
On startup, U-boot will turn on the left red LED, and turn off all other LEDs. When Linux starts up, it will by default turn the left red LED off, and the left green LED will act as a kernel heartbeat which will blink at rates depending on the system load.
The following LEDs are available on this system:
| LED | Linux Behavior |
|---|---|
| right-green-led | heartbeat trigger |
| right-red-led | Off |
| middle-yellow-led | Off |
| middle-green-led | Off |
| left-green-led | Off |
| left-yellow-led | Off |
| blu-led | Off |
| phy-0-led | f1072004.mdio-mii:00:1Gbps trigger [1] |
| phy-1-led | f1072004.mdio-mii:01:1Gbps trigger [1] |
These are accessed by writing to files:
# On
echo 1 > /sys/class/leds/right-red-led/brightness
# Off
echo 0 > /sys/class/leds/right-red-led/brightness
A number of triggers are also available, including timers, disk activity, and heartbeat. These allow the LEDs to represent various system activities as they occur. See the kernel LED documentation for more information on triggers and general use of LED class devices.