CS5535 datasheet(349/555 Pages) NSC

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KEL Register Descriptions (Continued)

5.10.2 KEL Native Registers

5.10.2.1

KEL HCE Control Register (KEL_HCE_CTRL)

KEL Memory Offset 100h

Type

R/W

Reset Value

00000000h

KEL_HCE_CTRL Register Map

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10

9876543210

RSVD

KEL_HCE_CTRL Bit Descriptions

Bit

Name

Description

31:9

RSVD

Reserved. Writes have no effect; reads return 0.

A20State

A20 State. Indicates current state of A20 on the LPC keyboard controller. Used to com-

pare against value written to I/O Port 060h when A20Sequence is active. A20State is

set and cleared only by software.

7IRQ12Active

IRQ12 Active. Indicates that a positive transition on IRQ12 from the LPC keyboard

controller has occurred. Software may write 1 to this bit to clear (0) it. A software write

of 0 to this bit has no effect.

IRQ1Active

IRQ1 Active. Indicates that a positive transition on IRQ1 from the LPC keyboard con-

troller has occurred. Software may write 1 to this bit to clear (0) it. A software write of a

0 to this bit has no effect.

A20Sequence

A20 Sequence. Set by KEL when a data value of D1h is written to I/O Port 064h.

Cleared by KEL on write to I/O Port 064h of any value other than D1h.

ExternalIRQEn

External Interrupt Request Enable. When set to 1, IRQ1 and IRQ12 from the LPC

keyboard controller causes an Emulation Event. The function controlled by this bit is

independent of the setting of the EmulationEnable bit (bit 0).

3IRQEn

Interrupt Request Enable. When set, the KEL generates IRQ1 or IRQ12 as long as

the OutputFull bit in HCE_Status is set to 1. If the AuxOutputFull bit of HceStatus is 0,

then IRQ1 is generated; if it is 1, then an IRQ12 is generated.

CharacterPending

Character Pending, When set, an EE is generated when the OutputFull bit of the

HCE_Status register is cleared to 0.

1Emulation

Interrupt (RO)

Emulation Interrupt (Read Only). This bit is a static decode of the EE state.

Returns 1 if: CharacterPending = 1

OR InputFull = 1

OR ExternalIRQEn = 1 AND (IRQ1Active OR IRQ12Active = 1).

EmulationEnable

Emulation Enable. When set to 1, the KEL is enabled for legacy emulation. The KEL

decodes accesses to I/O Port 060h and 064h and generates IRQ1 and/or IRQ12 when

appropriate. Additionally, the KEL generates an ASMI at appropriate times to invoke the

emulation software.

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