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4 HP BIOS
BIOS Addresses
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.
0378h - 037Ah Parallel port 1 (LPT1)
0388h - 038Bh AD1816 Ad-lib (FM)
03B0h - 03DFh Video controller
03E8h - 03EFh Serial port 3 (COM3)
03F0h - 03F5h Primary flexible disk drive controller
03F6h IDE primary channel
03F7h Primary flexible disk drive controller
03F8h - 03FFh Serial port 1 (COM1)
0678h - 067Bh Parallel port if ECP mode is selected 2 (LPT2 ECP)
0778h - 077Bh Parallel port if ECP mode is selected 1 (LPT1 ECP)
0CF8h - 0CFFh Configuration registers for PCI devices
8000 PIIX4 Power Management I/O space
8400 NS317 ACPI Registers
8800 PIIX4 SMBus I/O space
DMA controller
Channel Function
0 AD1816 Capture
1 AD1816 Playback
2 NS317 Flexible disk controller
3 NS317 LPT ECP
4 Cascade from first DMA controller
5Free
6Free
7Free
I/O Address Ports Function
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