Appendix B. System address maps 47
DMA I/O address map
The following figure lists resource assignments for the DMA address map. Any
addresses that are not shown are reserved.
03E0 – 03E7 8 Available
03E8 – 03EF 8 COM3 or COM4
03F0 – 03F5 6 Diskette channel 1
03F6 1 Primary IDE channel command port
03F7 (Write) 1 Diskette channel 1 command
03F7, bit 7 1 bit Diskette disk change channel
03F7, bits 6:0 7 bits Primary IDE channel status port
03F8 – 03FF 8 COM1
0400 – 047F 128 Available
0480 – 048F 16 DMA channel high page registers
0490 – 0CF7 1912 Available
0CF8 – 0CFB 4 PCI configuration address register
0CFC – 0CFF 4 PCI configuration data register
LPTn + 400h 8 ECP port, LPTn base address + hex 400
OCF9 1 Turbo and reset control register
0D00 – FFFF 62207 Available
Table 33. I/O address map
Address (hex) Size (bytes) Description
Table 34. DMA I/O address map
Address
(hex)
Description Bits
Byte
pointer
0000 Channel 0, memory address register 00 – 15 Yes
0001 Channel 0, transfer count register 00 – 15 Yes
0002 Channel 1, memory address register 00 – 15 Yes
0003 Channel 1, transfer count register 00 – 15 Yes
0004 Channel 2, memory address register 00 – 15 Yes
0005 Channel 2, transfer count register 00 – 15 Yes
0006 Channel 3, memory address register 00 – 15 Yes
0007 Channel 3, transfer count register 00 – 15 Yes
0008 Channels 0–3, read status/write command register 00 – 07
0009 Channels 0–3, write request register 00 – 02
000A Channels 0–3, write single mas register bits 00 – 02
000B Channels 0–3, mode register (write) 00 – 07
000C Channels 0–3, clear byte pointer (write) A
000D Channels 0–3, master clear (write)/temp (read) 00 – 07
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