Input/Output Interfaces
Audio Control
The audio subsystem is controlled through a set of indexed registers that physically reside in the audio codec . The register addresses are decoded by the audio controller and forwarded to the audio codec over the AC97 Link Bus previously described. The audio codec's control registers (Table
Table
AC97 Audio Codec Control Registers
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| Value |
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| Value |
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| Value |
Offset Address or | On | Offset Address or | On | Offset Address or | On | |||
Register | Reset | Register | Reset | Register | Reset | |||
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00h | Reset | 0100h | 14h | Video Vol. | 8808h | 28h | Ext. Audio ID. | 0001h |
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02h | Master Vol. | 8000h | 16h | Aux Vol. | 8808h | 2Ah | Ext. Audio Ctrl/Sts | 0000h |
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04h | Reserved | 18h | PCM Out Vol. | 8808h | 2Ch | PCM DAC SRate | BB80h | |
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06h | Mono Mstr. Vol. | 8000h | 1Ah | Record Sel. | 0000h | 32h | PCM ADC SRate | BB80h |
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08h | Reserved | 1Ch | Record Gain | 8000h | 34h | Reserved | ||
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0Ah | PC Beep Vol. | 8000h | 1Eh | Reserved | 72h | Reserved | ||
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0Ch | Phone In Vol. | 8008h | 20h | Gen. Purpose | 0000h | 74h | Serial Config. | 7x0xh |
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0Eh | Mic Vol. | 8008h | 22h | 3D Control | 0000h | 76h | Misc. Control Bits | 0404h |
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10h | Line In Vol. | 8808h | 24h | Reserved | 7Ch | Vender ID1 | 4144h | |
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12h | CD Vol. | 8808h | 26h | Pwr Mgnt. | 000xh | 7Eh | Vender ID2 | 5340h |
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Technical Reference Guide |