82801BA Datasheet, PDF (276/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

LPC Interface Bridge Registers (D31:F0)
9.1.24
9.1.25
RTC_CONF—RTC Configuration Register (LPC I/F—D31:F0)
Offset Address: D8h
Default Value: 00h
Lockable:
Yes
Attribute:
Size:
Power Well:
R/W
8-bit
Core
Bit
Description
7:5 Reserved.
Upper 128-byte Lock (U128LOCK)—R/W (special).
1 = Lock reads and writes to bytes 38h–3Fh in the upper 128 byte bank of the RTC CMOS RAM.
4
Write cycles to this range will have no effect and read cycles will not return any particular
guaranteed value. This is a write once register that can only be reset by a hardware reset.
0 = Access to these bytes in the upper CMOS RAM range have not been locked.
Lower 128-byte Lock (L128LOCK)—R/W (special).
1 = Locks reads and writes to bytes 38h–3Fh in the lower 128 byte bank of the RTC CMOS RAM.
3
Write cycles to this range will have no effect and read cycles will not return any particular
guaranteed value. This is a write once register that can only be reset by a hardware reset.
0 = Access to these bytes in the lower CMOS RAM range have not been locked.
Upper 128-byte Enable (U128E)—R/W.
2 ^{1 = Enables access to the upper 128 byte bank of RTC CMOS RAM.}
0 = Disable.
1:0 Reserved.
COM_DEC—LPC I/F Communication Port Decode Ranges
(LPC I/F—D31:F0)
Offset Address: E0h
Default Value: 00h
Lockable:
No
Attribute:
Size:
Power Well:
R/W
8-bit
Core
Bit
Description
7 Reserved
COMB Decode Range—R/W. This field determines which range to decode for the COMB Port.
000 = 3F8h–3FFh (COM1)
001 = 2F8h–2FFh (COM2)
010 = 220h–227h
6:4 _{011 = 228h–22Fh}
100 = 238h–23Fh
101 = 2E8h–2EFh (COM4)
110 = 338h–33Fh
111 = 3E8h–3EFh (COM3)
3 Reserved
COMA Decode Range—R/W. This field determines which range to decode for the COMA Port.
000 = 3F8h–3FFh (COM1)
001 = 2F8h–2FFh (COM2)
010 = 220h–227h
2:0 011 = 228h–22Fh
100 = 238h–23Fh
101 = 2E8h–2EFh (COM4)
110 = 338h–33Fh
111 = 3E8h–3EFh (COM3)
9-14
82801BA ICH2 and 82801BAM ICH2-M Datasheet