
AC ’97 Modem Controller Registers (D31:F6)
13-14
82801AA and 82801AB Datasheet
13.2.8
GLOB_CNT—Global Control Register
I/O Address:
Default Value:
Lockable:
MBAR + 3Ch
00000000h
No
Attribute:
Size:
Power Well:
R/W
32 bits
Core
13.2.9
GLOB_STA—Global Status Register
I/O Address:
Default Value:
Lockable:
MBAR + 40h
00000000h
No
Attribute:
Size:
Power Well:
R/W
32 bits
Core
Bit
Description
31:6
Reserved.
5
Secondary Resume Interrupt Enable
1 = Enable an interrupt to occur when the secondary codec causes a resume event on the AC-link.
0 = Disable
4
Primary Resume Interrupt Enable
1 = Enable an interrupt to occur when the primary codec causes a resume event on the AC-link.
0 = Disable
3
ACLINK Shut Off
1 = Disable the AC-link signals (drive all AC’97 outputs low and turn off all AC’97 input buffer
enables)
2
AC’97 Warm Reset.
1 = Writing a "1" to this bit causes a warm reset to occur on the AC-link. The warm reset awakens a
suspended codec without clearing its internal registers. If software attempts to perform a warm
reset while BIT_CLK is running, the write is ignored and the bit does not change. A warm reset
can only occur in the absence of BIT_CLK. This bit is self-clearing (it clears itself after the reset
has occurred and BIT_CLK has started).
1
AC‘97 Cold Reset#.
0 = Writing a "0" to this bit causes a cold reset to occur throughout the AC‘97 circuitry. All data in
the codec is lost. Software needs to clear this bit no sooner than after 1usec has elapsed. This
bit reflects the state of the AC_RST# pin. The ICH clears this bit to “0” upon entering S3/S4/S5
sleep states and PCIRST#.
0
GPI Interrupt Enable (GIE).
This bit controls whether the change in status of any GPI causes an
interrupt.
1 = The change on value of a GPI causes an interrupt and sets bit 0 of the Global Status Register.
0 = Bit 0 of the Global Status Register is set, but an interrupt is not generated.
Bit
Description
31:18
Reserved.
17
MD3:
Power down semaphore for Modem. This bit is used by software in conjunction with the AD3
bit to coordinate the entry of the two codecs into D3 state. This bit resides in the resume well and
maintains context across power states.
16
AD3:
Power down semaphore for Audio. This bit is used by software in conjunction with the MD3 bit
to coordinate the entry of the two codecs into D3 state
.
This bit resides in the resume well and
maintains context across power states.
15
Read Completion Status:
This bit indicates the status of Codec read completions.
1 = A Codec read results in a time-out. This bit remains set until being cleared by software.
0 = A Codec read completes normally.
14
Bit 3 of slot 12
: Display bit 3 of the most recent slot 12
13
Bit 2 of slot 12
: Display bit 2 of the most recent slot 12
12
Bit 1 of slot 12
: Display bit 1 of the most recent slot 12