Figure 1214. demand data-transfer mode with singl, Figure 12-14) – Intel 386 User Manual

Page 357

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Intel386™ EX EMBEDDED MICROPROCESSOR USER’S MANUAL

12-22

Figure 12-14. Demand Data-transfer Mode with Single Buffer-transfer Mode

After initialization, the DMA channel is

programmed with the requester and target

addresses and a byte count.

DMA gains bus control.

DMA transfers one byte or word of data

and decrements the byte count.

DMA channel relinquishes bus control.

Buffer transfer is complete, so channel

becomes idle.

Yes

No

DREQ

n

active?

Yes

No

DMA channel

relinquishes

bus control.

A2338-02

DREQ

n

active?

Yes

No

Byte

count = FFFFFFH

or EOP#

active?

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