ALIX system board
20
5/5/2010
Status LEDs
Status LEDs are all turned on by the BIOS on power up. The BIOS will turn off LEDs 2 and 3
before booting the operating system.
Location
GPIO
read port
write port
LED1 (left)
G6
port 06100h bit 6
port 06100h bit 6 / 22
LED2 (middle)
G25
port 06180h bit 9
port 06180h bit 9 / 25
LED3 (right)
G27
port 06180h bit 11
port 06180h bit 11 / 27
The CS5536 GPIO ports are programmed by 32 bit atomic writes. This avoids the need for read /
modify / write operations and the locking issues they entail. For example, to turn off LED1 (high),
write 0000’0040h to port 06100h. To turn on LED1 (low), write 0040’0000h. Multiple port bits can
be changed at the same time.
On ALIX.6, please note that LED3# is driven by the miniPCI express card by default. GPIO27
controls the W_DIS# radio inhibit signal instead. Drive low (0) to inhibit, high (1) to enable the
miniPCI express radio.
Mode switch
The mode switch can be accessed by software as follows:
Location
GPIO
read port
MODESW#
G24
port 061b0h bit 8
(active low, 0 = switch pressed)
Low level programming
Please see
www.pcengines.ch/file/alixllc.zip
for sample code.
