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
LED1 (left)
LED2 (middle)
LED3 (right)
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.
Mode switch
The mode switch can be accessed by software as follows:
Location
MODESW#
ALIX system board
GPIO
read port
G6
port 06100h bit 6
G25
port 06180h bit 9
G27
port 06180h bit 11
GPIO
read port
G24
port 061b0h bit 8
write port
port 06100h bit 6 / 22
port 06180h bit 9 / 25
port 06180h bit 11 / 27
(active low, 0 = switch pressed)
18
1/15/2008