8.2
Status & Control Register 2 (I/O address 211h)
NOTE
Bit 4 of this register is device locked.
7
6
5
4
3
2
1
0
|________|________|_________|________|_________|_________|_________|_________|
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|
|
|
|
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PC BUS
BIOS
THERM
SPEED
DEV
DEV
DEV
DEV
CLOCK
VSA
ALERT
STEP
UNLOCK
UNLOCK
UNLOCK
UNLOCK
SELECT
ENABLE
3
2
1
0
Bits 3 - 0: Device Lock (Write Only)
These bits control the Device Lock function. The device lock forces various Status and Control
Register bits to the clear (i.e. Zero) state following a power-on or reset. To unlock the device,
software should write 0X5h then 0XAh to this register.
Bit 4: SpeedStep (Read/Write Once)
0 = Low speed (battery optimized mode)
1 = High speed (performance mode)
This bit controls the logic that changes the processor operating frequency and voltage. This bit
will only respond to the first write to this register following a power-on or reset. Subsequent
writes to this register will not affect this bit.
NOTE
This feature is reserved for use by the BIOS only. User software may read this bit
(to determine the operating frequency) but may not change it.
Bit 5: Therm Alert Enable (Read/Write once)
0 = Therm Alert Disabled (Default)
1 = Therm Alert Enabled
This bit controls the logic that will turn the processor off if an over temperature condition occurs
in the processor chip. The MAX1617 which monitors the processor temperature is preset by the
BIOS to trip at a safe maximum level. The trip level should not be changed.
Bit 6: BIOS/VSA Select (Read/Write )
0 = BIOS ROM selected
1 = VSA ROM selected
This bit controls the selection of the BIOS or VSA ROMs. Normal operation requires that the
BIOS ROM be selected. VSA ROM selection is used for factory test.
Bit 7: P2 PCI Bus Speed (Read Only).
0 = 33MHz operation (VIO=5V)
1 = 66MHz operation (VIO=3.3V)
This bit directly reflects status of the P2_M66EN pin of the PMC PCI bus (bus 1).
8-4
VP 110/01x
Additional Local I/O Functions
Summary of Contents for VP 110/01 Series
Page 18: ...This page has been left intentionally blank 1 6 VP 110 01x Introduction and Overview ...
Page 60: ...This page has been left intentionally blank 7 6 VP 110 01x Memory ...
Page 88: ...This page has been left intentionally blank 9 8 VP 110 01x PC BIOS ...
Page 122: ...This page has been left intentionally blank 11 28 VP 110 01x VSA Mode Diagnostics ...
Page 150: ...This page has been left intentionally blank B 8 VP 110 01x Breakout Modules ...