Intel 6 SERIES CHIPSET - DATASHEET 01-2011 Datasheet page 723

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Integrated Intel High Definition Audio Controller Registers
17.1.2.31 IR—Immediate Response Register
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(Intel
Memory Address:HDBAR + 64h
Default Value:
Bit
Immediate Response Read (IRR) — RO. This register contains the response
received from a codec resulting from a command sent using the Immediate Command
mechanism.
31:0
If multiple codecs responded in the same time, there is no assurance as to which
response will be latched. Therefore, broadcast-type commands must not be issued
using the Immediate Command mechanism.
17.1.2.32 IRS—Immediate Command Status Register
®
(Intel
Memory Address:HDBAR + 68h
Default Value:
Bit
15:2 Reserved.
Immediate Result Valid (IRV) — R/WC.
1 = Set to 1 by hardware when a new response is latched into the Immediate Response
1
Software must clear this bit by writing a 1 to it before issuing a new command so that
the software may determine when a new response has arrived.
Immediate Command Busy (ICB) — R/W. When this bit is read as 0, it indicates that
a new command may be issued using the Immediate Command mechanism. When this
bit transitions from a 0 to a 1 (using software writing a 1), the controller issues the
command currently stored in the Immediate Command register to the codec over the
link. When the corresponding response is latched into the Immediate Response register,
the controller hardware sets the IRV flag and clears the ICB bit back to 0. Software may
0
write this bit to a 0 if the bit fails to return to 0 after a reasonable time out period.
NOTE: An Immediate Command must not be issued while the CORB/RIRB mechanism
Datasheet
High Definition Audio Controller—D27:F0)
00000000h
High Definition Audio Controller—D27:F0)
0000h
register (HDBAR + 64). This is a status flag indicating that software may read the
response from the Immediate Response register.
is operating, otherwise the responses conflict. This must be enforced by
software.
Attribute: RO
Size: 32 bits
Description
Attribute: R/W, R/WC
Size: 16 bits
Description
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