YMF744B

3Fh: Maximum Latency

Read Only

Default: 19h

Access Bus Width: 8, 16, 32-bit

b7

b6

b5

b4

b3

b2

b1

b0

Maximum Latency

b[7:0] ..........Maximum Latency

This register indicates how often DS-1S generates the Bus Master Request.

This register is hardwired to 19h.

40-41h: Legacy Audio Control

Read / Write

Default: 907Fh

Access Bus Width: 8, 16, 32-bit

b15

b14

b13

 

b12

 

b11

b10

b9

b8

b7

b6

b5

b4

b3

b2

b1

b0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LAD

SIEN

 

MPUIRQ

 

 

SBIRQ

 

SDMA

I/O

MIEN

MEN

GPEN

FMEN

SBEN

b0................SBEN: Sound Blaster Enable

This bit enables the mapping of the Sound Blaster Pro block in the I/O space specified by the SBIO bits, when LAD is set to “0”. The FM Synthesizer registers can be accessed via SB I/O space, while the SB block is enabled, even if FMEN is set to “0”.

 

“0”: Disable the mapping of the SB block to the I/O space

 

 

“1”: Enable the mapping of the SB block to the I/O space

(default)

b1................FMEN: FM Synthesizer Enable

 

 

 

This bit enables the mapping of the FM Synthesizer block in the I/O space specified by the FMIO bits,

 

when LAD is set to “0”. FM Synthesizer registers can be accessed via SB I/O space, while the SB block

 

is enabled, even if FMEN is set to “0”.

 

 

 

“0”: Disable the mapping of the FM Synthesizer block to the FMIO space

 

“1”: Enable the mapping of the FM Synthesizer block to the FMIO space (default)

 

After setting FMEN to “1”, about 100 msec is necessary before accessing these I/O space.

b2

................GPEN: Gameport Enable

 

 

 

This bit enables the mapping of the Joystick block in the I/O space specified by the JSIO bits, when LAD

 

is set to “0”.

 

 

 

“0”: Disable the mapping of the Joystick block

 

 

 

“1”: Enable the mapping of the Joystick block

(default)

 

b3

................MEN: MPU401 Enable

 

 

 

This bit enables the mapping of the MPU401 block in the I/O space specified by the MPUIO bits, when

 

LAD is set to “0”.

 

 

 

“0”: Disable the mapping of the MPU401 block

 

 

 

“1”: Enable the mapping of the MPU401 block

(default)

 

February 3, 1999

-18-

Page 18
Image 18
Yamaha YMF744B (DS-1S) specifications 3Fh Maximum Latency, 40-41h Legacy Audio Control

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.