Very, very handy guide to the RasPi status LEDs, from RaspberryPi Spy:
All Raspberry Pi boards have status LEDs positioned in one corner next to the 3.5mm audio jack and USB port(s).
The Model B has five status LEDs whereas the Model A has two. The Model A has PCB labels for all the LEDs but the three network related LEDs are not populated.
The [above] photo shows the five status LEDs on a Raspberry Pi Model B Rev 2.0 board (Note the mounting hole not present on the original Model B Rev 1.0 devices).
Revision 1.0 Boards (Model B) labels are :
Revision 2.0 Board (Model A & Model B) labels are :
The LEDs have the following meanings :
- ACT – D5 (Green) – SD Card Access
- PWR – D6 (Red) – 3.3 V Power is present
- FDX – D7 (Green) – Full Duplex (LAN) connected
- LNK – D8(Green) – Link/Activity (LAN)
- 100 – D9(Yellow) – 100Mbit (LAN) connected
Each Friday is PiDay here at Adafruit, be sure to check out our posts, tutorials and new Raspberry Pi related products. Have you tried the new “Adafruit Raspberry Pi Educational Linux Distro” ? It’s our tweaked distribution for teaching electronics using the Raspberry Pi. But wait, there’s more! Try our new Raspberry Pi WebIDE! The easiest way to learn programming on a Raspberry Pi.
We now have Raspberry Pi Model B with 512MB RAM in stock and shipping now!