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Chapter 26  DMA Controller

4.Operation Flowcharts

This section contains operation flowcharts for the following transfer modes:

• Block transfer

• Burst transfer

• Demand transfer

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■

Load the initial address,

transfer count, and number 

of blocks

Activation request

wait

Interrupt clear

DMA transfer end

DMA interrupted

BLK=0

DTC=0

DMA stop

DENB=1

DENB=>0

Write back the address, 

transfer count, and 

number of blocks

Number of blocks - 1

Activation request

One-time access for fly-by

Reload enable

Only when the peripheral
interrupt activation source
is selected

Calculate the address for 

transfer source address access

Calculate the address for transfer

destination address access

Block transfer
-  Can be activated by all activation sources (selection).
-  Can access to all areas.
-  The number of blocks can be set.
-  Interrupt clear is issued when transfer of the specified 
   number of blocks is completed.
-  The DMA interrupt is issued when transfer for the number 
   of times specified is completed.

Transfer count - 1

Interrupt cleared