82801DB Datasheet, PDF (510/587 Pages) Intel Corporation – Intel 82801DB I/O Controller Hub 4 (ICH4)

AC ’97 Modem Controller Registers (D31:F6)
15.2.10
CAS—Codec Access Semaphore Register
I/O Address:
Default Value:
Lockable:
NABMBAR + 44h
00h
No
Attribute:
Size:
Power Well:
Reads across DWord boundaries are not supported.
R/W
8 bits
Core
Bit
Description
7:1 Reserved
Codec Access Semaphore (CAS) — R/W-Special. This bit is read by software to check whether a
codec access is currently in progress.
0 0 = No access in progress.
1 = The act of reading this register sets this bit to 1. The driver that read this bit can then perform
an I/O access. Once the access is completed, hardware automatically clears this bit.
510
Intel^® 82801DB ICH4 Datasheet