Confidential Draft
3/7/00
CS4281 Programming Manual
84
DS308PRM1
10.4.5
ISA Interrupt Select Register (IISR)
Address:
BA0: 3F4h, Read-Write
PCI CFG: 0F4h, Read-Write if CWPR configured, otherwise Read-Only
Default:
00000000h
Definition: Vaux powered. Defines the ISA interrupt associated with a particular pin and relays flags from
BIOS to the OS and host software. This register is unaffected by the PCI
RST#
signal. The default
value is set by a Vaux POR signal.
Bit Descriptions:
VAUXS
Vaux Support. This bit is reflected into the D3
cold
support bit,
PMC.PMD3C
. BIOS code
would generally set this bit (through config space) if VAUX is supported.
VAC[2:0]
Vaux Current. These bits are reflected in the
PMC.VAC[2:0]
bits and must be initialized by the
BIOS to indicate how much current Vaux pulls. Note this is total current and is the combined
CS4281 and any attached Codecs and external logic using Vaux.
000 - 0 mA (self powered/don’t support Vaux)
001 - 55 mA
010 - 100 mA
011 - 160 mA
100 - 220 mA
101 - 270 mA
110 - 320 mA
111 - 375 mA (spec maximum)
AUXP
Auxiliary Power. This bit is reflected in the
PMC.AUXP
bit. Not sure what this bit does yet.
BCF[2:0]
BIOS Configuration Flags. These bits are read-writable and available in config. and host
memory space. They have no direct affect on the operation of the CS4281 and may be used by
host software when communicating with the BIOS.
GTD
Global Trapping Disable. When set, disables all I/O trapping including overriding the
IOTCR.ITD
bit. When
GTD
is clear,
IOTCR.ITD
controls all I/O trapping.
IRQA[3:0]
IRQA
pin interrupt mapping. A 0 disables (high impedance) the corresponding ISA interrupt
pin. A non-zero value (preferably the actual ISA interrupt connected to the pin) allows the pin
to be enabled through the ISA interrupt enable bit
IIER.IAEN
.
IRQB[3:0]
IRQB
pin interrupt mapping. A 0 disables (high impedance) the corresponding ISA interrupt
pin. A non-zero value (preferably the actual ISA interrupt connected to the pin) allows the pin
to be enabled through the ISA interrupt enable bit
IIER.IBEN
.
IRQC[3:0]
IRQC
pin interrupt mapping. A 0 disables (high impedance) the corresponding ISA interrupt
pin. A non-zero value (preferably the actual ISA interrupt connected to the pin) allows the pin
to be enabled through the ISA interrupt enable bit
IIER.ICEN
.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
VAUXS
VAC2
VAC1
VAC0
AUXP
BCF2
BCF1
BCF0
GTD
IRQC3
IRQC2
IRQC1
IRQC0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
IRQB3
IRQB2
IRQB1
IRQB0
IRQA3
IRQA2
IRQA1
IRQA0
D
ra
ft
Содержание CS4281
Страница 8: ...Confidential Draft 3 7 00 CS4281 Programming Manual 8 DS308PRM1 D r a f t...
Страница 12: ...Confidential Draft 3 7 00 CS4281 Programming Manual 12 DS308PRM1 D r a f t...
Страница 24: ...Confidential Draft 3 7 00 CS4281 Programming Manual 24 DS308PRM1 D r a f t...
Страница 34: ...Confidential Draft 3 7 00 CS4281 Programming Manual 34 DS308PRM1 D r a f t...
Страница 44: ...Confidential Draft 3 7 00 CS4281 Programming Manual 44 DS308PRM1 D r a f t...
Страница 114: ...Confidential Draft 3 7 00 CS4281 Programming Manual 114 DS308PRM1 D r a f t...
Страница 192: ...Confidential Draft 3 7 00 CS4281 Programming Manual 192 DS308PRM1 D r a f t...