Compaq Deskpro Workstation AP230 - Figure 4-12. Slim Desktop;C

Technical Reference Guide
Compaq Deskpro Personal Computers
Third Edition - April 2001
4-37
High and low thermal parameters are programmed into the ASIC by BIOS during POST. If the
high thermal parameter is reached then the fan(s) will be turned on full speed and the Therm-
signal will be asserted. The asserted Therm- signal can, with the proper software setup, be used by
the 82801 ICH2 to initiate an AOL message for transmission over a network (refer to Network
Interface Controller subsection in Chapter 5).
NOTE: These systems do not support thermister-based fans used on earlier products.
NOTES:
[1] Will be +12 VDC if fan is connected.
Figure 4-11. Small Form Factor Fan Control Block Diagram
NOTES:
[1] Will be +12 VDC if chassis or boxed fan is connected and turned on.
Figure 4-12. Slim Desktop/Configurable Minitower Fan Control Block Diagram
Power Supply Assembly
P1
Speed
Control
Fan CMD
Fan Off-
Fan
Off
Fan
SPD
Processor
Sensing
ASIC
On/Off
Control
(+)
(-)
Fan
Sink
Fan
Sense
[
1
]
(+)
(-)
2
3
4
Chassis Fan
Header
SMBus
ICH2
82801
ICH2
Therm-
On/Off
Control
(-)
(+)
3
2
1
Heat Sink Fan Header
P70
8
12
24
PS Fan
Power Supply Assembly
P1
Speed
Control
Fan CMD
Fan Off-
Fan
Off
Fan
SPD
Processor
Sensing
ASIC
On/Off
Control
(+)
(-)
Fan
Sense [1]
SMBus
ICH2
82801
ICH2
Therm-
10
13
PS Fan
Speed
Control
+12 VDC
(-)
(+)
3
2
1
Heat Sink Fan Header
P70
Interrupt