YMF744B View Datasheet(PDF) - Yamaha Corporation

Part Name

Description

Manufacturer

YMF744B

3.3V; DS-1S high performance audio controller for the PCI bus

Yamaha Corporation 

YMF744B

b14..............SIEN: Serialized IRQ enable

DS-1S supports 3 types of interrupt protocols: PCI interrupt (INTA#), Legacy interrupt (IRQs) and

Serialized IRQ. The interrupt protocol is selected with IMOD and SIEN as follows.

The interrupt channels for IRQs and Serialized IRQ are determined by SBIRQ and MPUIRQ,. Only one

protocol can be used at once.

SIEN IMOD Interrupt protocol

0

0

Legacy interrupt (IRQs)

(default)

0

1

PCI interrupt (INTA#)

1

*

Serialized IRQ

b15..............LAD: Legacy Audio Disable

This bit disables the Legacy Audio block.

“0”: Enables the Legacy Audio block

“1”: Disables the Legacy Audio block

(default)

When this bit is set to “1”, DS-1S does not respond to the I/O Target transaction for legacy I/O address on

the PCI bus.

42-43h: Extended Legacy Audio Control

Read / Write

Default: 0000h

Access Bus Width: 8, 16, 32-bit

b15 b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0

IMOD SBVER

SMOD

-

- MAIM -

-

-

-

-

-

-

-

b8................MAIM: MPU401 Acknowledge Interrupt Mask

This bit determine whether interrupt is asserted when the acknowledge, which is occurred by changing

MPU401 mode form default to UART, is returned.

“0”: Interrupt is asserted when the acknowledge is returned.

(default)

“1”: Interrupt is masked when the acknowledge is returned.

b[12:11] ......SMOD: SB DMA mode

These bits determine the protocol to achieve the DMAC(8237) function on the PCI bus.

“0”:

PC/PCI

(default)

“1”:

reserved

“2”:

Distributed DMA

“3”

reserved

February 3, 1999

-20-

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