Configuration Jumpers

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Advanced/ZP Jumper Settings

Updated: Tuesday, August 6, 1996

Contents

Jumper Locations and Definitions
Microprocessor Configuration
Setup Disable
Clear CMOS
Password Clear
VR/VRE
ISA Bus Clock
Recovery Boot Enable/Bus Frequency

Jumper Locations and Definitions

Microprocessor Configuration

Note: Several versions of the Advanced/ZP motherboard were manufactured, each supporting a different set of Pentium processor speeds. See the Advanced/ZP Frequently Asked Questions for information on how to identify the different versions.

External CPU Clock Speed (Switches 7 & 8)
These switches set the CPU's external operating frequency at 50, 60, or 66 MHz. Default setting depends on the specific product code; see the table below for specific Pentium processor configuration information.

Internal CPU Clock Speed (Switch 6)
Sets the internal processor speed to either 1.5 or 2 times the external CPU clock speed. Switch 6 is OFF for 1.5, Switch 6 is ON for 2 times. The 1.5 setting is used for 75 MHz, 90 MHz, and 100 MHz processors. The 2 times setting is used for 120 MHz processors.

The following table gives the position of Switches 6, 7 and 8:

Pentium Processor Type	Switch 8	Switch 7	Switch 6	Switch 2
50/75 MHz	off	off	off	*
60/90 MHz	off	on	off	*
66/100 MHz	on	off	off	*
Reserved	on	on	n/a	*
Reserved	off	off	on	*
60/120 MHz	off	on	on	*
66/133 MHz	on	off	on	*

*The VR/VRE setting is dependent on the specific processor type.

Setup Disable (Switch 5)
Allows access to CMOS Setup Utility to be disabled by setting switch 5 to the ON position. Default is for access to setup to be enabled (switch 5 = OFF).

Clear CMOS (Switch 4)
Allows CMOS settings to be reset to default values by moving switch 4 to the ON position and turning the system on. The system should then be turned off and switch 4 should be returned to the OFF position to restore normal operation. This procedure should be done whenever the system BIOS is updated. Default setting is SW4=OFF.

Password Clear (Switch 3)
Allows system password to be cleared by moving switch 3 to the ON position and turning the system on. The system should then be turned off and switch 3 should be returned to the OFF position to restore normal operation. This procedure should only be done if the user password has been forgotten. Default setting is SW3=OFF.

VR/VRE (Switch 2)
Sets the output of the on-board voltage regulator. The switch settings are OFF = VR, and ON = VRE. The VR voltage specification requires a voltage range of 3.3-3.465 Volts DC, while the VRE specification requires a voltage range of 3.45-3.6V. Pentium processors that do not require the VRE voltage specification should use the VR setting. When upgrading your CPU be sure to consult the documentation for the processor voltage requirements before setting this switch, as an incorrect setting may damage the processor. The default position is with the switch set for VR (off).

ISA Bus Speed (Switch 1)
Sets the ISA bus speed to either 1/4 or 1/3 of the PCI bus speed to best maximize system performance for 75, 90, 100 or 120 MHz processor speeds. When SW1=ON the ISA bus speed will be 1/4 of the PCI bus speed and when SW1=OFF the ISA bus speed will be 1/3 the PCI bus speed. The ISA bus speed is derived from the PCI bus speed which is derived from the external processor clock frequency. The position of SW1 will set the ISA bus speed to either Compatible or Enhanced for 90 MHz, 100 MHz, and 120 MHz processors and will leave the ISA bus speed Compatible for 75 MHz processor speed. For 90 MHz, 100 MHz, and 120 MHz processor speeds, if SW1 is set to Compatible (SW1=ON), the speed will fall within the limits defined by the IBM AT Technical Reference (6-8.33 MHz). If set to Enhanced (SW1=OFF), the speed will be greater than the maximum defined by the IBM AT Technical Reference manual. SW1 can be set to either position when a 75 MHz processor speed is used for maximum ISA bus performance. Modern ISA cards can operate with the enhanced speeds, however some older cards can experience difficulties. The actual value of the Bus Clock when set to Compatible or Enhanced is dependent upon the setting of the external processor frequency. The following table describes the ISA bus speeds for the 75 MHz, 90 MHz, 100 MHz, and 120 MHz processor speeds.

Internal Processor Frequency	PCI Bus Freq.	Switch 1=OFF (1/3)	Switch 1=ON (1/4)
75 MHz	25 MHz	8.33 MHz	8.33 MHz
90 MHz	30 MHz	10.0 MHz	7.50 MHz
100 MHz	33 MHz	11.0 MHz	8.33 MHz
120 MHz	30 MHz	10.0 MHz	7.50 MHz

Recovery Boot Enable (Jumper J1K1)
This switch allows the system to boot in the event the system BIOS has been corrupted by moving the jumper from the default position of 1-2 to the 2-3 position. A recovery disk must be in drive A while booting up with this jumper set to 2-3. Once the recovery is complete the jumper should be move back to pins 1-2, and the system rebooted.