H8SXSLASH1663R datasheet(450/1504 Pages) RENESAS

450 / 1504 page

Section 10 DMA Controller (DMAC)

Rev. 2.00 Sep. 24, 2008 Page 418 of 1468

REJ09B0412-0200

10.5.6

Address Update Function using Offset

The source and destination addresses are updated by fixing, increment/decrement by 1, 2, or 4, or

offset addition. When the offset addition is selected, the offset specified by the offset register

(DOFR) is added to the address every time the DMAC transfers the data access size of data. This

function realizes a data transfer where addresses are allocated to separated areas.

Figure 10.17 shows the address update method.

±0

+ offset

±1, 2, or 4

Address not

updated

Data access size

added to or subtracted

from address (addresses

are continuous)

Offset is added to address

(addresses are not

continuous)

(a) Address fixed

(b) Increment or decrement

by 1, 2, or 4

External memory

Figure 10.17 Address Update Method

In item (a), Address fixed, the transfer source or destination address is not updated indicating the

same address.

In item (b), Increment or decrement by 1, 2, or 4, the transfer source or destination address is

incremented or decremented by the value according to the data access size at each transfer. Byte,

word, or longword can be specified as the data access size. The value of 1 for byte, 2 for word, and

4 for longword is used for updating the address. This operation realizes the data transfer placed in

consecutive areas.

In item (c), Offset addition, the address update does not depend on the data access size. The offset

specified by DOFR is added to the address every time the DMAC transfers data of the data access

size.

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