82371FB Datasheet, PDF (47/122 Pages) Intel Corporation – 82371FB (PIIX) AND 82371SB (PIIX3) PCI ISA IDE XCELERATOR

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82371FB (PIIX) AND 82371SB (PIIX3)
2.2.24. CTHTMR—CLOCK SCALE STPCLK# HIGH TIMER (Function 0)
Address Offset:
Default Value:
Attribute:
AEh
00h
Read/Write
The value in this register defines the duration of the STPCLK# negated period when bit 2 in the SMICNTL
Register is set to 1. The value in this register is loaded into the STPCLK# Timer when STPCLK# is negated.
The STPCLK# timer is a divide by PCI clock. The base count for a value of 0 is 42 µsec for a 50 MHz time
base, 35 µsec for a 60 MHz time base, 32 µsec for a 66 MHz time base. These numbers are determined as
follows: # of PCI clocks STPCLK# is asserted (or negated) = 1 + 1056 X (programmed value in register +1).
Bit
Description
7:0
Clock Scaling STPCLK# High Timer Value. Bits [7:0] define the duration of the STPCLK#
negated period during clock throttling.
2.3. PCI Configuration Registers—IDE Interface (Function 1)
The PIIX/PIIX3 are multi-function devices, as indicated by bit 7 of the Header Type Register. The PCI IDE
interface function uses Function 1.
2.3.1. VID—Vendor Identification Register (Function 1)
Address Offset:
Default Value:
Attribute:
00–01h
8086h
Read Only
The VID Register contains the vendor identification number. This register, along with the Device Identification
Register, uniquely identify any PCI device. Writes to this register have no effect.
Bit
Description
15:0 Vendor Identification Number. This is a 16-bit value assigned to Intel
2.3.2. DID—DEVICE IDENTIFICATION REGISTER (Function 1)
Address Offset:
Default Value:
Attribute:
02–03h
1230h (PIIX)
7010h (PIIX3)
Read Only
The DID Register contains the device identification number. This register, along with the VID Register, define
the PIIX. Writes to this register have no effect.
Bit
Description
15:0 Device Identification Number. This is a 16-bit value assigned to the PIIX.
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