LM4560 datasheet(15/54 Pages) NSC

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3.0 Register Description (Continued)

Bit7..0

Legacy FmMusic Bank 0 Register

Index

Read

Bit 7

FmMusic Timer Interrupt Flag (Equal

to Bit 6 + Bit 5)

Bit 6

FmMusic Timer 1 Overflowed Flag

Bit 5

FmMusic Timer2 Overflowed Flag

Bit 4..0

Reserved

Relative Internal Function Register File

In order to emulate the legacy FmMusic(YMF262 or OPL3)

function, a 512 bytes register file (RAM) must be imple-

mented. By legacy access method, this register file has two

banks and the bank index is specified by SBR0 and SBR2

respectively. This register file is byte-wide format, read/write

RAM which has no high speed operation requirement.

Relative Internal Functional Register Extracted From

Legacy FmMusic Bank 0 Register File

FmMusic-TIMER1

Bank Index: 02h

Size:

8 bits

Type:

Read/Write

Default:

00h

Bit 7..0

Timer1 Preset Value

If enabled, Timer1 counter will increase every 1024 AC97 bit-

clock (12.288 MHz). When overflow occurs, this value is re-

loaded into the counter.

FmMusic-TIMER2

Bank Index: 03h

Size:

8 bits

Type:

Read/Write

Default:

00h

Bit 7..0

Timer2 Preset Value

If enabled, Timer2 counter will increase every 4096 AC97 bit-

clock (12.288 MHz). When overflow occurs, this value is re-

loaded into the counter.

FmMusic-Timer-CONTROL

Bank Index: 04h

Size:

8 bits

Type:

Read/Write

Default:

00h

Bit 7

Reset Bit 7–5 of Legacy FmMusic

Status Register

Bit 6

Reset Timer1 Overflow Flag

Bit 5

Reset Timer2 Overflow Flag

Bit 4–2

Reserved

Bit 1

Enable Timer 2

Bit 0

Enable Timer 1

Bit 7–5 must be self-cleared to 0 after it is written as 1.

When bit 1 or 0 is set from 0 to 1, the corresponding timer

counter will load its preset value and start counting. When

these bits are zero, the respective timer counter will stop

counting. If bit 1 is set 1, bit 7 and 5 of FmMusic Status reg-

ister will be set 1 when timer2 is overflowed. If bit 0 is set 1,

bit 7 and 6 of FmMusic Status register will be set 1 when

timer1 is overflowed.

3.4.2.2 SBR1 (Legacy FmMusic Bank 0 Register Data

Port)

Address: AudioBase + 11h or SBBase + 1h or SBBase +

09h or ADLIBBase + 1h or AudioBase + 13h or

SBBase + 3h or ADLIBBase + 3h

Size:

8 bits

Type:

Read/Write

Default:

XXh

Bit 7..0

Legacy FmMusic Bank 0 Register

(indexed by SBR0) Data

When writing to this register, if SBR0 is B0h–B8h and bit 5 of

the content (indexed by SBR0) is changed from 0 to 1 or vice

versa, or SBR0 is BDh and any one of bit 4–0 of the content

(indexed by SBR0) is changed from 0 to 1 or vice versa, an

OPL3 Bank0 Key On/Off Dirty Flag will be set in the Audio

Status Registers ASR0 and AOPLSR0.

3.4.2.3 SBR2 (Legacy FmMusic Bank 1 Register Index)

Address: AudioBase + 12h || SBBase + 2h || ADLIBBase +

Size:

8 bits

Type:

Read/Write

Default:

00h

Bit 7..0

Legacy FmMusic Bank 1 Register

Index

3.4.2.4 SBR3 (Legacy FmMusic Bank 1 Register Data

Port)

Address: AudioBase + 11h or SBBase + 1h or ADLIBBase

+ 1h or AudioBase + 13h or SBBase + 3h or

ADLIBBase + 3h

Size:

8 bits

Type:

Read/Write

Default:

XXh

Bit 7..0

Legacy FmMusic Bank 1 Register

(indexed by SBR2) Data

When write to this register, if SBR2 is B0h–B8h and bit 5 of

the content (indexed by SBR2) is changed from 0 to 1 or vice

versa, an OPL3 Bank1 Key On/Off Dirty Flag will be set in

Audio Status Registers ASR0 and AOPLSR0.

3.4.2.5 SBR4 (Legacy Sound Blaster Mixer Register

Index)

Address: AudioBase + 14h or SBBase + 4h

Size:

8 bits

Type:

Read/Write

Default:

00h

Bit 7..0

Legacy SB16 / SBPRO Mixer

3.4.2.6 SBR5 (Legacy Sound Blaster Mixer Register

Data Port)

Address: AudioBase + 15h or SBBase + 5h

Size:

8 bits

Type:

Read/Write

Default:

XXh

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