82NM10 Datasheet, PDF (153/671 Pages) Intel Corporation – Intel® NM10 Family Express Chipset

Functional Description
For some other loss (e.g., Microsoft MS-DOS*) the BIOS should restore the timer back
to 54.6 ms before passing control to the operating system. If the BIOS is entering ALT
access mode before entering the suspend state it is not necessary to restore the timer
contents after the exit from ALT access mode.
5.14.10.1 Write Only Registers with Read Paths in ALT Access Mode
The registers described in Table 5-64 have read paths in ALT access mode. The access
number field in the table indicates which register will be returned per access to that
port.
Table 5-64.Write Only Registers with Read Paths in ALT Access Mode (Sheet 1 of 2)
Restore Data
Restore Data
I/O
Addr
# of
Rds
Access
Data
I/O
Addr
# of
Rds
Access
Data
00h
2
01h
2
02h
2
03h
2
04h
2
05h
2
06h
2
1
DMA Chan 0 base address
low byte
40h 7
2
DMA Chan 0 base address
high byte
1
DMA Chan 0 base count low
byte
2
DMA Chan 0 base count high
byte
1
DMA Chan 1 base address
low byte
2
DMA Chan 1 base address
high byte
1
DMA Chan 1 base count low
byte
2
DMA Chan 1 base count high
41h 1
byte
1
DMA Chan 2 base address
low byte
42h 1
2
DMA Chan 2 base address
high byte
70h 1
1
DMA Chan 2 base count low
C4h 2
byte
2
DMA Chan 2 base count high
byte
1
DMA Chan 3 base address
low byte
C6h 2
2
DMA Chan 3 base address
high byte
1
Timer Counter 0 status,
bits [5:0]
2
Timer Counter 0 base
count low byte
3
Timer Counter 0 base
count high byte
4
Timer Counter 1 base
count low byte
5
Timer Counter 1 base
count high byte
6
Timer Counter 2 base
count low byte
7
Timer Counter 2 base
count high byte
Timer Counter 1 status,
bits [5:0]
Timer Counter 2 status,
bits [5:0]
Bit 7 = NMI Enable,
Bits [6:0] = RTC Address
1
DMA Chan 5 base address
low byte
2
DMA Chan 5 base address
high byte
1
DMA Chan 5 base count
low byte
2
DMA Chan 5 base count
high byte
Datasheet
153