Yamaha YMF744B (DS-1S) 42-43h Extended Legacy Audio Control, B1211 ......SMOD SB DMA mode

Models: YMF744B (DS-1S)

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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)

01 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

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Yamaha YMF744B (DS-1S) specifications 42-43h Extended Legacy Audio Control, B14..............SIEN Serialized IRQ enable

YMF744B (DS-1S) specifications

The Yamaha YMF744B, also known as the DS-1S, is a popular audio chip that emerged in the late 1990s, particularly known for its use in sound cards for PCs. This sound processor exemplifies Yamaha's commitment to delivering high-quality audio through innovative technology and user-friendly features.

One of the standout features of the YMF744B is its ability to support advanced sound synthesis methods, including wave table synthesis and sample playback. These technologies provide users with a rich audio experience, enabling high-fidelity sounds reminiscent of live instruments. The chip is also notable for its ability to emulate MIDI instruments, allowing musicians to create synthesized music that captures the nuances of traditional sounds.

The YMF744B integrates a 16-bit DAC (Digital-to-Analog Converter), which facilitates high-quality audio playback with a sampling rate of up to 48 kHz. This capability ensures that sound reproduction remains clear and devoid of distortion, appealing to both casual users and audio professionals alike. Additionally, the chip supports multiple audio channels, making it ideal for gaming and multimedia applications where spatial audio is crucial.

Another significant feature of the YMF744B is its support for various audio formats, including PCM (Pulse Code Modulation), ADPCM (Adaptive Differential Pulse Code Modulation), and even MIDI. The versatility in format support allows users to interact with a broad spectrum of audio applications, from game design to music production.

The chip also comes with integrated Sound Blaster Pro compatibility, which significantly enhances its usability with a vast array of software and games designed during the 1990s and early 2000s. This compatibility is crucial for retro gaming enthusiasts who seek an authentic audio experience with classics from the past.

Moreover, the YMF744B champions power efficiency, making it an attractive choice for mobile computing platforms. Its low power consumption means that it can be effectively used in laptops without significantly draining battery life, allowing users to enjoy high-quality sound on the go.

In summary, the Yamaha YMF744B (DS-1S) stands out due to its advanced audio synthesis capabilities, high-quality playback features, and compatibility with multiple formats. These attributes make it a favored choice in the audio processing domain, continuing to impact computer audio technology long after its initial release.