Intel® HD Audio (D27:F0)
10.3.37 SDFIFOS—Stream Descriptor FIFO Size Register
Memory Address:
Input Stream[0]: LBAR + 90h
Input Stream[1]: LBAR + B0h
Output Stream[0]: LBAR + D0h
Output Stream[1]: LBAR + F0h
Input Stream: 0077h
Attribute: Input: RO
Output:
R/W, RO
Default Value:
Size:
16 bits
Output Stream: 00BFh
Default
Bit
and
Description
Access
00h
RO
15:8
Reserved
FIFO Size — RO (Input stream), R/W (Output stream): Indicates the
maximum number of bytes that could be fetched by the controller at one
time. This is the maximum number of bytes that may have been DMA’d
into memory but not yet transmitted on the link, and is also the maximum
possible value that the PICB count will increase by at one time.
The value in this field is different for input and output streams. It is also
dependent on the Bits per Samples setting for the corresponding stream.
Following are the values read/written from/to this register for input and
output streams, and for non-padded and padded bit formats:
Output Stream R/W value:
Value
Output Streams
8, 16, 20, 24, or 32 bit Output
Streams
0Fh = 16B
8, 16, 20, 24, or 32 bit Output
Streams
1Fh = 32B
3Fh = 64B
7Fh = 128B
77h
RO
(input)
8, 16, 20, 24, or 32 bit Output
Streams
8, 16, 20, 24, or 32 bit Output
Streams
7:0
BFh
R/W
(output)
BFh = 192B
FFh = 256B
8, 16, or 32 bit Output Streams
20, 24 bit Output Streams
NOTES:
1.
2.
All other values not listed are not supported.
When the output stream is programmed to an unsupported size,
the hardware sets itself to the default value (BFh).
Software must read the bit field to test if the value is supported
after setting the bit field.
3.
Input Stream RO value:
Value
Input Streams
77h = 120B
9Fh = 160B
8, 16, 32 bit Input Streams
20, 24 bit Input Streams
NOTE: The default value is different for input and output streams, and
reflects the default state of the BITS fields (in Stream Descriptor
Format registers) for the corresponding stream.
166
Datasheet
INTEL [ INTEL ]
