Product specifications

VT8235 V-Link South Bridge
Revision 1.22 October 24, 2002 -104- Device 17 Function 5 Audio Controller Registers
I/O Offset x2 – DXS Left Channel x Volume (3Fh)........RW
I/O Offset x3 – DXS Right Channel x Volume (3Fh) .....RW
7-6 Reserved (Do Not Program)............always write 0’s
5-0 Volume Control
000000 0 db
… …
000111 -10.5 db
… …
011111 -46.5 db
… …
111111 Muted (instead of -94.5 db) .............. default
I/O Offset x7-x4 – DXS Chan x SGD Table Ptr Base.....RW
31-0 SGD Table Pointer Base Address (even addr).... W
Current Pointer Address........................................R
I/O Offset xB-x8 – StopIndex / DataType / SampleRateRW
31-24 SGD Stop Index Setting.......................default = FFh
23-22 Reserved ........................................ always reads 0
21-20 PCM Format
Selects the format used by the controller to process
the incoming sample.
00 8-bit Mono............................................. default
01 8-bit Stereo
10 16-bit Mono
11 16-bit Stereo
19-0 Sample Rate.........................default = FFFFFh (48K)
This field allows the sample rate converter to know
the sample rate of an incoming sample so the
converter can properly convert the sample into the
required 48 KHz sample output. Program as (2
20
/
48.000) * Sample Rate
I/O Offset xF-xC – DXS Chan x SGD Current Count....RO
31-24 Current SGD Index
This field reports the index the SGD engine is
currently processing.
23-0 Current SGD Count
This field reports the count remaining in the current
entry being processed. For example, if 10 bytes of a
30-byte count have been transferred, this field would
read 20 to indicate 20 bytes remaining.
Audio SGD Table Format
63
62 61-56 55-32 31-0
EOL FLAG -reserved- Base Base
Count Address
[23:0] [31:0]
EOL End Of Link
. 1 indicates this block is the last of the
link. If the channel “Interrupt on EOL” bit is set,
then an interrupt is generated at the end of the
transfer.
FLAG Block Flag
. If set, transfer pauses at the end of this
block. If the channel “Interrupt on FLAG” bit is set,
then an interrupt is generated at the end of this block.