CS5530A datasheet(68/259 Pages) NSC

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Functional Description (Continued)

Table 3-22. Secondary Hard Disk Idle Timer and Trap Related Registers

Bit

Description

F0 Index 83h

Power Management Enable Register 4 (R/W)

Reset Value = 00h

Secondary Hard Disk Idle Timer Enable: Load timer from Secondary Hard Disk Idle Timer Count Register (F0 Index ACh)

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[4], 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 86h/F6h[4].

Secondary 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[4], 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[5].

F0 Index 93h

Miscellaneous Device Control Register (R/W)

Reset Value = 00h

Partial Secondary Hard Disk Decode: This bit is used to restrict the addresses which are decoded as secondary hard

Disk accesses.

0 = Power management monitors all reads and writes I/O Port 170h-177h, 376h

1 = Power management monitors only writes to I/O Port 176h and 177h

F0 Index ACh-ADh

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

Reset Value = 0000h

15:0

Secondary Hard Disk Idle Timer Count: The idle timer loaded from this register is used to determine when the secondary

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

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

whenever an access occurs to the configured secondary hard disk’s data port (configured in F0 Index 93h[4]). The timer

uses a 1 second timebase.

To enable this timer set F0 Index 83h[7] = 1.

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

Second level SMI status is reported at F0 Index 86h/F6h[4].

CS5530A Datasheet(PDF) 68 Page - National Semiconductor (TI)