Intel PXA255 - Manual (Page 471)

Intel® PXA255 Processor Developer’s Manual 13-21
AC’97 Controller Unit
13.8.3.2 Global Status Register (GSR)
This is a read/write register. Ignore reads from reserved bits. Write zeros to reserved bits.
5 SECRES_IEN
Secondary Resume Interrupt Enable:
0 = Interrupt is disabled
1 = Enables an interrupt to occur when the Secondary CODEC causes a resume event on
the AC-link
4 PRIRES_IEN
Primary Resume Interrupt Enable:
0 = Interrupt is disabled
1 = Enables an interrupt to occur when the Primary CODEC causes a resume event on the
AC-link
3 ACLINK_OFF
AC-link Shut Off:
0 = If the AC-link was off, turns it back on, otherwise this bit has no effect.
1 = Causes the ACUNIT to drive SDATA_OUT and SYNC outputs low and turn off input
buffer enables. The reset output is however maintained high. The AC-link will not be
allowed to access any of the FIFOs.
Setting this bit does not ensure a clean shut down. Software must make sure that all
transactions are complete before setting this bit.
2 WARM_RST
AC’97 Warm Reset
0 = A warm reset is not generated.
1 = Causes a warm reset to occur on the AC-link. The warm reset will awaken a
suspended CODEC without clearing it’s internal registers.
If software attempts to perform a warm reset while BITCLK is running, the write will be
ignored and the bit will not change. This bit is self clearing i.e., it remains set until the reset
completes and BITCLK is seen on the AC-link after which it clears itself.
1 COLD_RST
AC'97 Cold Reset
0 = Causes a cold reset to occur throughout the AC'97 circuitry. All data in the ACUNIT
and the CODEC will be lost.
1 = A cold reset is not generated.
Defaults to 0. After reset, the driver must to set this bit to a 1.The value of this bit is retained
after suspends, hence, if this bit was set to a 1 before a suspend, a cold reset is not
generated on a resume.
0 GIE
CODEC GPI Interrupt Enable (GIE)
This bit controls whether the change in status of any Modem CODEC GPI causes an
interrupt.
0 = If this bit is not set, bit 0 of the Global Status Register is set, but an interrupt is not
generated.
1 = If this bit is set, the change in value of a GPI (as indicated by bit 0 of slot 12) causes an
interrupt and sets bit 0 of the Global Status Register
Table 13-7. GCR Bit Definitions (Sheet 2 of 2)
Physical Address
4050_000C
GCR Register AC’97 Controller Unit
Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
reserved
CD
ON
E_
IE
SD
O
N
E_
IE
reserved
SEC
RD
Y_
IEN
PR
IR
DY
_
IE
N
rese
rved
SEC
RE
S_
IEN
P
R
IR
ES_IEN
AC
L
INK
_
O
F
F
WA
R
M
_
R
S
T
CO
L
D
_
R
ST
GI
E
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Bits Name Description