Dma Channel Controllers - HP Vectra VEi8 Technical Reference Manual

3 BIOS Overview
BIOS Addresses
Applies only if a
supplementary ISA
card is installed

DMA Channel Controllers

Only "I/O-to-memory" and "memory-to-I/O" transfers are allowed.
"I/O-to-I/O" and "memory-to-memory" transfers are disallowed by the
hardware configuration.
The system controller supports seven DMA channels, each with a page
register used to extend the addressing range of the channel to 16 MB.
The following table summarizes how the DMA channels are allocated.
1.
2.
38
I/O Address Ports
03B0 - 03DF VGA
03E8 - 03EF COM3
03F0h- 03F5 Floppy disk drive controller
03F6 IDE primary channel
03F7 Floppy disk drive controller
03F8 - 03FF COM1
04D0 - 04D1 Interrupt edge/level control
0678 - 067B LPT2 ECP
0778 - 077B LPT1 ECP
0CF8 - 0CFF PCI configuration space
DMA controller
Channel
0 Free
Free if not used for parallel port or audio in Setup
1
2 Floppy disk controller
Free if not used for parallel port or audio in Setup
3
4 Used to cascade DMA channels 0-3
5 Free
6 Free
7 Free
DMA 1 is used for the parallel port by default
DMA 3 is used by audio by default
Function
Function
1
2