Address Update Function Using Offset; Figure 7.17 Address Update Method - Renesas H8SX/1500 Series Hardware Manual

Section 7 DMA Controller (DMAC)
7.4.6

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 7.17 shows the address update method.
Address not
updated
(a) Address fixed
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.
Rev. 3.00 Mar. 14, 2006 Page 172 of 804
REJ09B0104-0300
±0
Data access size
added to or subtracted
from address (addresses
are continuous)
(b) Increment or decrement
by 1, 2, or 4

Figure 7.17 Address Update Method

±1, 2, or 4
Offset is added to address
(addresses are not
continuous)
(c) Offset addition
+ offset