(^242) PC Hardware: A Beginner’s Guide
DMA devices are assigned one of the eight DMA channels available, which cannot be
shared by two devices. The expansion card that is typically assigned a DMA channel is
the sound card, which may actually get two or more channels, if they are available. The
most common assignments of DMA channels are listed in Table 11-3.
Device I/O Address Assignment
Primary IDE 1F0–1F7h
Games port 0200–0207h
Sound card 0220–022Fh
Plug and Play 0270–0273h
Parallel port 0278–027Ah
Network adapter 0300–031F
VGA adapter 03C0–03DF
PCMCIA port 03E0–03E7
Direct memory access (DMA)
Table 11-2. Default I/O Address Assignments on a PC
DMA Channel Assignments
0 Reserved for system
1 Sound card (8-bit transfer)
2 Floppy disk controller (8-bit transfer)
3 Open (8-bit transfer)
4 Link to DMA channels 0-3
5 Sound card (16-bit transfer)
6 Open (16-bit transfer)
7 Open (16-bit transfer)
Table 11-3. Default DMA Channel Assignments on a PC
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