Figure 1228. dma software request register (dmasr – Intel 386 User Manual

Page 378

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12-43

DMA CONTROLLER

Read DMASRR to see whether a software request for a particular channel is pending. Each re-
quest bit is cleared upon Terminal Count or external EOP#. When in auto-initialize mode, both
bits are cleared when a Terminal Count or external EOP# occurs.

Figure 12-28. DMA Software Request Register (DMASRR – read format)

DMA Software Request

(read format)

DMASRR

Expanded Addr:
ISA Addr:
Reset State:

F009H
0009H
00H

7

0

SR1

SR0

Bit

Number

Bit

Mnemonic

Function

7–2

Reserved. These bits are undefined; for compatibility with future devices,
do not modify these bits.

1

SR1

Software Request 1:

When set, this bit indicates that channel 1 has a software request
pending.

0

SR0

Software Request 0:

When set, this bit indicates that channel 0 has a software request
pending.

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