32581CCore Logic Module - ISA Legacy Register Space

 

 

 

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

Bit

 

Description

 

 

I/O Port 0D0h (R/W)

 

 

 

 

Read

 

 

DMA Status Register, Channels 7:4

Note:

Channels 5, 6, and 7 are not supported.

 

 

 

7

 

Channel 7 Request. Indicates if a request is pending.

 

 

0:

No.

 

 

1:

Yes.

 

 

 

6

 

Channel 6 Request. Indicates if a request is pending.

 

 

0:

No.

 

 

1:

Yes.

 

 

 

5

 

Channel 5 Request. Indicates if a request is pending.

 

 

0:

No.

 

 

1:

Yes.

 

 

 

4

 

Undefined.

 

 

 

3

 

Channel 7 Terminal Count. Indicates if TC was reached.

 

 

0:

No.

 

 

1:

Yes.

 

 

 

2

 

Channel 6 Terminal Count. Indicates if TC was reached.

 

 

0:

No.

 

 

1:

Yes.

 

 

 

1

 

Channel 5 Terminal Count. Indicates if TC was reached.

 

 

0:

No.

 

 

1:

Yes.

 

 

 

0

 

Undefined.

 

 

 

 

Write

 

 

DMA Command Register, Channels 7:4

Note:

Channels 5, 6, and 7 are not supported.

 

 

 

7

 

DACK Sense.

 

 

0:

Active low.

 

 

1:

Active high.

 

 

 

6

 

DREQ Sense.

 

 

0:

Active high.

 

 

1:

Active low.

 

 

 

5

 

Write Selection.

 

 

0:

Late write.

 

 

1:

Extended write.

 

 

 

4

 

Priority Mode.

 

 

0:

Fixed.

 

 

1:

Rotating.

 

 

 

3

 

Timing Mode.

 

 

0:

Normal.

 

 

1: Compressed.

 

 

 

2

 

Channels 7:4.

 

 

0:

Disable.

 

 

1:

Enable.

 

 

 

1:0

 

Reserved. Must be set to 0.

 

 

 

 

298

AMD Geode™ SC3200 Processor Data Book

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AMD SC3200 manual Undefined, Write DMA Command Register, Channels, 298