BCT-ETX-C3-XXX
S
INGLE
B
OARD
C
OMPUTER
I
NSTALLATION
D
IRECT
M
EMORY
A
CCESS
C
HANNELS
(DMA)
DMA Channel
Use
Description
0
Used to be for memory refresh on early PCs. Available on ETX-C3
1
If Soundblaster is enabled in the BIOS setup this is occupied, else
available
2
Floppy
Reserved for the floppy disk controller
3
LPT
If Parallel port is setup in the BIOS to ECP mode this is occupied,
else available
4
Cascaded
Reserved for second set of DMA channels
5
Available
6
Available
7
Available
I/O
A
DDRESS
M
AP
(
HEX
)
I/O Address
Description
0000 - 00lF
DMA Controller 1
0020 - 003F
Interrupt Controller 1, Master
0040 - 005F
Timer & Index registers for UMC491
0060 - 006F
8042 (Keyboard & Mouse)
0070 - 007F
Real Time Clock, NMI Mask
0080 - 008F
POST & DMA Page Register
00A0 - 00BF
Interrupt Controller 2, Slave
00C0 - 00DF
DMA Controller 2
00F0
Clear Maths Coprocessor Busy
00F1
Reset Maths Coprocessor
00F8 - 00FF
Maths Coprocessor
0100 - 010F
Watchdog, E²PROM, Byte Wide Socket & Software selection of serial ports
01F0 - 01F8
Hard (Fixed) Disk Controller
0208 - 021A
EMS Page registers (either 208 or 218, etc.)
02F8 - 02FF
Serial Port 2
0360 - 036F
Reserved
0378 - 037F
Parallel Printer Port 1
03B0 - 03DF
Video Adapter
03F0 - 03F7
Floppy Diskette Controller
03F8 - 03FF
Serial Port 1
1000 +
Can be allocated by PCI devices either onboard or on the host board