Core Logic Module - ISA Legacy Register Space

32580B

 

 

 

Table 6-43. DMA Channel Control Registers (Continued)

 

Bit

 

Description

 

 

 

 

 

I/O Port 0D2h

Software DMA Request Register, Channels 7:4 (W)

 

Note:

Channels 5, 6, and 7 are not supported.

 

 

 

 

 

7:3

 

Reserved. Must be set to 0.

 

 

 

 

 

2

 

Request Type.

 

 

 

0:

Reset.

 

 

 

1:

Set.

 

 

 

 

 

1:0

 

Channel Number Request Select.

 

 

 

00:

Illegal.

 

 

 

01:

Channel 5.

 

 

 

10:

Channel 6.

 

 

 

11:

Channel 7.

 

 

 

 

 

 

I/O Port 0D4h

DMA Channel Mask Register, Channels 7:4 (WO)

 

Note:

Channels 5, 6, and 7 are not supported.

 

 

 

 

 

7:3

 

Reserved. Must be set to 0.

 

 

 

 

 

2

 

Channel Mask.

 

 

 

0: Not masked.

 

 

 

1: Masked.

 

 

 

 

 

1:0

 

Channel Number Mask Select.

 

 

 

00: Channel 4.

 

 

 

01: Channel 5.

 

 

 

10: Channel 6.

 

 

 

11: Channel 7.

 

 

 

 

 

 

I/O Port 0D6h

DMA Channel Mode Register, Channels 7:4 (WO)

 

Note:

Channels 5, 6, and 7 are not supported.

 

 

 

 

 

7:6

 

Transfer Mode.

 

 

 

00: Demand.

 

 

 

01: Single.

 

 

 

10: Block.

 

 

 

11: Cascade.

 

 

 

 

 

5

 

Address Direction.

 

 

 

0:

Increment.

 

 

 

1: Decrement.

 

 

 

 

 

4

 

Auto-initialize.

 

 

 

0:

Disabled

 

 

 

1: Enable

 

 

 

 

 

3:2

 

Transfer Type.

 

 

 

00:

Verify.

 

 

 

01: Write transfer (I/O to memory).

 

 

 

10: Read transfer (memory to I/O).

 

 

 

11: Reserved.

 

 

 

 

 

1:0

 

Channel Number Mode Select.

 

 

 

00: Channel 4.

 

 

 

01: Channel 5.

 

 

 

10: Channel 6.

 

 

 

11: Channel 7.

 

 

 

Channel 4 must be programmed in cascade mode. This mode is not the default.

 

 

 

 

 

 

I/O Port 0D8h

DMA Clear Byte Pointer Command, Channels 7:4 (W)

 

Note:

Channels 5, 6, and 7 are not supported.

 

 

 

 

I/O Port 0DAh

DMA Master Clear Command, Channels 7:4 (W)

 

Note:

Channels 5, 6, and 7 are not supported.

 

 

 

 

I/O Port 0DCh

DMA Clear Mask Register Command, Channels 7:4 (W)

 

Note:

Channels 5, 6, and 7 are not supported.

 

 

 

 

 

 

 

 

 

AMD Geode™ SC2200 Processor Data Book

309

Page 297
Image 297
AMD SC2200 manual Bit Description Port 0D2h, Port 0D4h, Port 0D6h, Port 0D8h, Port 0DAh, Port 0DCh