Figure 7.18 Operation Of Offset Addition - Renesas H8SX/1520 Series Hardware Manual

The address is calculated by the offset set in DOFR and the contents of DSAR and DDAR.
Although the DMAC calculates only addition, an offset subtraction can be realized by setting the
negative value in DOFR. In this case, the negative value must be 2's complement.
(1)
Basic Transfer Using Offset
Figure 7.18 shows a basic operation of a transfer using the offset addition.
Offset
Offset
Offset
Offset
In figure 7.18, the offset addition is selected as the transfer source address update and increment or
decrement by 1, 2, or 4 is selected as the transfer destination address. The address update means
that data at the address which is away from the previous transfer source address by the offset is
read from. The data read from the address away from the previous address is written to the
consecutive area in the destination side.
Downloaded from Elcodis.com electronic components distributor
Data 1 Address A1
Data 2 Address A2
= Address A1 + Offset
Data 3
Address A3
= Address A2 + Offset
Data 4 Address A4
= Address A3 + Offset
Address A5
Data 5
= Address A4 + Offset

Figure 7.18 Operation of Offset Addition

Data 1
Transfer
Data 2
Data 3
Data 4
Data 5
:
:
:
:
Transfer source: Offset addition
Transfer destination: Increment by 4 (longword)
Rev. 3.00 Mar. 14, 2006 Page 173 of 804
Section 7 DMA Controller (DMAC)
Address B1
Address B2 = Address B1 + 4
Address B3 = Address B2 + 4
Address B4 = Address B3 + 4
Address B5 = Address B4 + 4
REJ09B0104-0300