IBM 2289, 6824 manual DMA I/O address map, Address hex Description Bits Byte pointer

Address range (hex)		Size (bytes)	Description
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

DMA I/O address map

The following table lists resource assignments for the DMA address map. Any addresses that are not shown are reserved.

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)	N/A
000D	Channels 0–3, master clear (write)/temp (read)	00 – 07
000E	Channels 0-3, clear mask register (write)	00 – 03
000F	Channels 0-3, write all mask register bits	00 – 03
0081	Channel 2, page table address register	00 – 07
0082	Channel 3, page table address register	00 – 07
0083	Channel 1, page table address register	00 – 07
0087	Channel 0, page table address register	00 – 07
0089	Channel 6, page table address register	00 – 07
008A	Channel 7, page table address register	00 – 07
008B	Channel 5, page table address register	00 – 07
008F	Channel 4, page table address/refresh register	00 – 07
00C0	Channel 4, memory address register	00 – 15	Yes
00C2	Channel 4, transfer count register	00 – 15	Yes

Appendix C. System address maps 39