GL815E Endura Motherboard Product Manual
Page 20 of 51
ISA Slots
The motherboard provides 2 ISA slots, one of which is shared with a PCI slot. The National
Semiconductor NS87200 provides the PCI to ISA bridge. In order to fully support the ISA bus power
rails, the ATX power supply should provide –5V. Since the motherboard makes no use of this rail, it
need not be provided if the ISA adapters do not require it.
Support for ISA card option ROMs is possible only if certain BIOS features are disabled –
see the BIOS section for details.
2.14 System management
The GL8"5E motherboard includes hardware system management functions integrated into the
National Semiconductor PC87366 Super I/O (SIO) device. They monitor system voltages,
motherboard and CPU temperatures, fan speed and control system fans. The following sections
describe this in more detail. The BIOS Setup utility can be used to display the status of the system
monitors.
2.14.1 Voltage Monitoring
The table below details the motherboard voltage rails monitored and their usage.
Voltage Rail Usage on Motherboard
+"2V Serial ports, processor voltage generation, audio quiet supply, fans.
+5.0V Processor voltage generation, internal logic, keyboard, mouse, USB and
video ports.
+3.3V
Chipset ICH2, firmware hub, ISA bridge, audio CODEC, SIO, clock
generator, flat panel controller.
+2.5V Clock generator.
+".8V Chipset GMCH, chipset ICH2.
+".5V Processor bus termination, processor signaling.
-"2V Serial ports.
VCPU Processor core voltage.
+3.3V Standby Primary standby voltage to systems that control motherboard wake-up,
System memory DIMMs, Ethernet controller.
VBAT* This rail is used to power the RTC and the CMOS RAM.
* The VBAT supply is generated from the +3.3V standby supply when available in order to preserve
the life of the lithium cell. This means, however, that the voltage read via the monitor is that of the
standby rail and not of the lithium cell itself.
A regulator on the motherboard generates the processor operating voltage with each processor
selecting the correct voltage automatically. The table below indicates the correct operating voltage
for the different processors.
