CS5530A datasheet(67/259 Pages) NSC

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Functional Description (Continued)

Table 3-21. Primary Hard Disk Idle Timer and Trap Related Registers

Bit

Description

F0 Index 81h

Power Management Enable Register 2 (R/W)

Reset Value = 00h

Primary Hard Disk Idle Timer Enable: Load timer from Primary Hard Disk Idle Timer Count Register (F0 Index 98h) and

generate an SMI when the timer expires. 0 = Disable; 1 = Enable.

If an access occurs in the address ranges selected in F0 Index 93h[5], the timer is reloaded with the programmed count.

Top level SMI status is reported at F1BAR+Memory Offset 00h/02h[0].

Second level SMI status is reported at F0 Index 85h/F5h[0].

F0 Index 82h

Power Management Enable Register 3 (R/W)

Reset Value = 00h

Primary Hard Disk Trap: 0 = Disable; 1 = Enable.

If this bit is enabled and an access occurs in the address ranges selected in F0 Index 93h[5], an SMI is generated.

Top level SMI status is reported at F1BAR+Memory Offset 00h/02h[0].

Second level SMI status is reported at F0 Index 86h/F6h[0].

F0 Index 93h

Miscellaneous Device Control Register (R/W)

Reset Value = 00h

Partial Primary Hard Disk Decode: This bit is used to restrict the addresses which are decoded as primary hard disk

accesses.

0 = Power management monitors all reads and writes I/O Port 1F0h-1F7h, 3F6h

1 = Power management monitors only writes to I/O Port 1F6h and 1F7h

F0 Index 98h-99h

Primary Hard Disk Idle Timer Count Register (R/W)

Reset Value = 0000h

15:0

Primary Hard Disk Idle Timer Count: The idle timer loaded from this register is used to determine when the primary hard

disk is not in use so that it can be powered down. The 16-bit value programmed here represents the period of primary hard

disk inactivity after which the system is alerted via an SMI. The timer is automatically reloaded with the count value when-

ever an access occurs to the configured primary hard disk’s data port (configured in F0 Index 93h[5]). The timer uses a 1

second timebase.

To enable this timer set F0 Index 81h[0] = 1.

Top level SMI status is reported at F1BAR+Memory Offset 00h/02h[0].

Second level SMI status is reported at F0 Index 85h/F5h[0].

CS5530A Datasheet(PDF) 67 Page - National Semiconductor (TI)