©2008 Advanced Micro Devices, Inc. AC ’97 Controller Functional Descriptions
AMD SB600 Register Reference Manual Proprietary Page 225
Output DMA 1/2/3 FIFO Info– R - 32 bits - [MEM_Reg: 70h]
Field Name Bits Default Description
out DMA3 Used 14:10 00h Number of filled FIFO entries of Output DMA3 (FIFO
size 6).
Reserved 15 0b
out DMA1 Free 20:16 00h Number of free FIFO entries of Output DMA1 (FIFO
size 6).
out DMA2 Free 25:21 00h Number of free FIFO entries of Output DMA2 (FIFO
size 6).
out DMA3 Free 30:26 00h Number of free FIFO entries of Output DMA3 (FIFO
size 6).
Reserved 31 0b
Output DMA1/2/3 FIFO Used/Free Register:
GPIO Out Data– RW - 32 bits - [MEM_Reg: 74h]
Field Name Bits Default Description
Gpio Out Data en 0 0b Enables the sending of GPIO data on the next frame’s
slot 12. Data comes from bit[20:1] of this register. This
bit has higher priority than reg0x08[22]. That means if
both this bit and reg0x08[22] are set, then GPIO data
comes from bit[20:1] of this register, not from DMA3.
Writing 1 to this bit enables this data to be sent out.
After some time, when data is sent out, this bit
automatically goes back to 0. Bit[20:1] can be written
only when this bit is 0.
Gpio Out Data 20:1 000h Gpio Out Data
Reserved 31:21 000h
Gpio Out Data Register: Data to the modem.
Input GPIO Data– R - 32 bits - [MEM_Reg: 78h]
Field Name Bits Default Description
Input Gpio data 19:0 00000h Input Gpio(modem) data from AC'97 Codecs (ORed)
Input Gpio Codec ID 22:20 0h ID of Codec who send the Gpio data (001 - Master,
010- Slave1, 100 - Slave2)
Reserved 31:23 00h
Input Gpio data Register: Data from the modem.
Modem Mirror– RW - 32 bits - [MEM_Reg: 7Ch]
Field Name Bits Default Description
Modem mirror 31:0 0000_0000h Data written by modem for communication with Audio.
Modem mirror Register.
Audio Mirror– R - 32 bits - [MEM_Reg: 80h]
Field Name Bits Default Description
Audio mirror 31:0 0000_0000h Data written by audio for communication with modem.
Audio mirror Register.
Modem Fifo Flush– W - 32 bits - [MEM_Reg: 88h]
Field Name Bits Default Description
Output DMA1 Fifo Flush 0 0b Writing to this bit flushes modem output DMA1 fifo,
i.e., the indexes and Used/Free counts are reset.
Reading this bit returns 0.
Output DMA2 Fifo Flush 1 0b Writing to this bit flushes modem output DMA2 fifo,
i.e., the indexes and Used/Free counts are reset.
Reading this bit returns 0.