H8SXSLASH1663R datasheet(527/1504 Pages) RENESAS

527 / 1504 page

Section 11 EXDMA Controller (EXDMAC)

Rev. 2.00 Sep. 24, 2008 Page 495 of 1468

REJ09B0412-0200

11.5.6

Address Update Function Using Offset

There are the following update methods for transfer destination and source addresses: Fixed,

increment/decrement by 1, 2 or 4, and offset addition. With the offset addition method, the offset

specified by the offset register (EDOFR) is added each time the EXDMAC performs a data-

access-size transfer. This function allows the mid-addresses being skipped during data transfer.

Figure 11.17 shows the address update methods.

±0

+ Offset

±1, 2, or 4

Address not

updated

Value, that corresponds

to data access size,

incremented, decremented

to/from the address

(Successive addresses)

(a) Fixed

(b) Increment/decrement

by 1, 2 or 4

External memory

Offset value added to the address

(Insuccessive addresses)

Figure 11.17 Address Update Method

For the fixed method (a), the same address is always indicated without the transfer destination or

source address being updated.

For the method of increment/decrement by 1, 2 or 4 (b), the value corresponding to the data access

size is incremented or decremented to or from the transfer destination or source address each time

the data is transferred. A byte, word, or longword can be specified for the data access size. The

value used for increment or decrement of an address is 1 for a byte-size , 2 for a word-size , and 4

for a longword-size transfer. This function allows continuous address transfer of EXDMAC.

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