CS5530 datasheet(70/241 Pages) NSC

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Revision 4.1

Functional Description (Continued)

3.4.3.2

General Purpose Timers

The CS5530 contains two general purpose idle timers,

General Purpose Timer 1 (F0 Index 88h) and General

Purpose Timer 2 (F0 Index 8Ah). These two timers are

similar to the Device Idle Timers in that they count down

to zero unless re-triggered, and generate an SMI when

they reach zero. However, these are 8-bit timers instead

of 16 bits, they have a programmable timebase, and the

events which reload these timers are configurable. These

timers are typically used for an indication of system inac-

tivity for Suspend determination.

General Purpose Timer 1 can be re-triggered by activity to

any of the configured user defined devices, keyboard and

mouse, parallel and serial, floppy disk, or hard disk.

General Purpose Timer 2 can be re-triggered by a transi-

tion on the GPIO7 pin (if GPIO7 is properly configured).

Configuration of the GPIO7 is explained in Section 3.4.3.4

“General Purpose I/O Pins” on page 73.

When a General Purpose Timer is enabled or when an

event reloads the timer, the timer is loaded with the config-

ured count value. Upon expiration of the timer an SMI is

generated and a status flag is set. Once expired, this

counter must be re-initialized by disabling and enabling it.

The timebase for both General Purpose Timers can be

configured as either 1 second (default) or 1 millisecond.

The registers at F0 Index 89h and 8Bh are the control reg-

isters for the General Purpose Timers. Table 3-27 show

the bit formats for these registers.

Table 3-27. General Purpose Timers and Control Registers

Bit

Description

F0 Index 88h

General Purpose Timer 1 Count Register (R/W)

Reset Value = 00h

7:0

General Purpose Timer 1 Count: This field represents the load value for GP Timer 1. This value can represent either an

8-bit or 16-bit counter (selected in F0 Index 8Bh[4]). It is loaded into the counter when the timer is enabled (F0 Index

83h[0] =1). Once enabled, an enabled event (configured in F0 Index 89h[6:0]) reloads the timer.

The counter is decremented with each clock of the configured timebase. Upon expiration of the counter, an SMI is gener-

ated and the top level SMI status is reported at F1BAR+Memory Offset 00h/02h[9]. The second level SMI status is

reported at F1BAR+Memory Offset 04h/06h[0]).

Once expired, this counter must be re-initialized by either disabling and enabling it, or writing a new count value here.

This counter’s timebase can be configured as 1 msec or 1 sec at F0 Index 89h[7].

F0 Index 89h

General Purpose Timer 1 Control Register (R/W)

Reset Value = 00h

Timebase for General Purpose Timer 1: Selects timebase for GP Timer 1 (F0 Index 88h): 0 = 1 sec; 1 = 1 msec.

Re-trigger General Purpose Timer 1 on User Defined Device 3 (UDEF3) Activity: 0 = Disable; 1 = Enable.

Any access to the configured (memory or I/O) address range for UDEF3 reloads GP Timer 1. UDEF3 address

programming is at F0 Index C8h (base address register) and CEh (control register).

Re-trigger General Purpose Timer 1 on User Defined Device 2 (UDEF2) Activity: 0 = Disable; 1 = Enable.

Any access to the configured (memory or I/O) address range for UDEF2 reloads GP Timer 1. UDEF2 address

programming is at F0 Index C4h (base address register) and CDh (control register).

Re-trigger General Purpose Timer 1 on User Defined Device 1 (UDEF1) Activity: 0 = Disable; 1 = Enable.

Any access to the configured (memory or I/O) address range for UDEF1 reloads GP Timer 1. UDEF1 address

programming is at F0 Index C0h (base address register) and CCh (control register)

Re-trigger General Purpose Timer 1 on Keyboard or Mouse Activity: 0 = Disable; 1 = Enable

Any access to the keyboard or mouse I/O address range (listed below) reloads GP Timer 1.

Keyboard Controller: I/O Ports 060h/064h

COM1: I/O Port 3F8h-3FFh (if F0 Index 93h[1:0] = 10 this range is included)

COM2: I/O Port 2F8h-2FFh (if F0 Index 93h[1:0] = 11 this range is included)

Re-trigger General Purpose Timer 1 on Parallel/Serial Port Activity: 0 = Disable; 1 = Enable.

Any access to the parallel or serial port I/O address range (listed below) reloads the GP Timer 1.

LPT1: I/O Port 378h-37Fh, 778h-77Ah

LPT2: I/O Port 278h-27Fh, 678h-67Ah

COM1: I/O Port 3F8h-3FFh (if F0 Index 93h[1:0] = 10 this range is excluded)

COM2: I/O Port 2F8h-2FFh (if F0 Index 93h[1:0] = 11 this range is excluded)

COM3: I/O Port 3E8h-3EFh

COM4: I/O Port 2E8h-2EFh

Re-trigger General Purpose Timer 1 on Floppy Disk Activity: 0 = Disable; 1 = Enable.

Any access to the floppy disk drive address ranges (listed below) reloads GP Timer 1.

Primary floppy disk: I/O Port 3F2h-3F5h, 3F7h

Secondary floppy disk: I/O Port 372h-375h, 377h

The active floppy drive is configured via F0 Index 93h[7].

Re-trigger General Purpose Timer 1 on Primary Hard Disk Activity: 0 = Disable; 1 = Enable.

Any access to the primary hard disk drive address range selected in F0 Index 93h[5] reloads GP Timer 1.

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