Xilinx Understanding AC97 Audio Features, AC97 Pinout, and LM4550 Integration

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Chapter 2: ML310 Embedded Development Platform

send byte/receive byte/ write byte/write word/read word/block read/block write command with clock synchronization function as well as 10-bit addressing ability. Please see Section “IIC/SMBus Interface” for more information regarding the devices that are connected to the SMBus. Please review the ALi M1535D+ Data sheets for more detailed information.

AC97 Audio

The ALi South Bridge has a built-in Audio that is combined with a standard AC97 CODEC, LM4550. Below is a list of the features available to the user. The ALi M1535D+ is used in conjunction with an LM4550. Please review the ALi M1535D+ and LM4550 Data sheets, located on the ML310 CDROM, for more detailed information.

♦AC97 CODEC 2.1 Specification Compliant

♦CODEC Variable Sample Rate Support

♦32-voice Hardware Wave-table Synthesis

♦32 Independent DMA _channels

♦3D Positioning Sound Acceleration

♦Legacy Sound Blaster compatible

♦FM OPL3 emulation

♦MIDI Interpretation

♦MIDI MPU-401 interface

The ML310 employs a National Semiconductor, LM4550, Audio CODEC combined with the ALi South Bridge AC97 interface. This interface can be used to play and record audio. The LM4550 has a left and right channel Line inputs, a microphone input, left and right channel line outputs and an amplified version headphone output suitable for driving an 8 ohm load via LM4880 (U2). The audio jacks are available on the J1 and J2 connector assemblies. Please consult the M1535D+, LM4550 and LM4880 data sheets in conjunction with the ML310 schematics for more details on the ML310 Audio interface.

Table 2-19describes the audio jacks available to the user on the ML310.

Table 2-19:Audio Jacks, J1 and J2

Audio Jack	Signal name	Description
J1 top	AC _AMP_OUTR	AC Amplified Output,
	AC _AMP_OUTL	driven by U2, LM4880
J1 Bottom	AC_MIC_IN	Microphone Input to U1, LM4550
J2 Top	AC _LINE_OUTR	AC Line Output, Left and Right channels,
	AC _LINE_OUTL	driven by U1, LM4550
J2 Bottom	AC _LINE_INR	AC Line Input, Left and Right channels,
	AC_LINE_INL	driven by U1, LM4550

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