HD6417751 Datasheet, PDF (953/1105 Pages) Renesas Technology Corp – SuperH RISC engine

Only longword access size is supported in the case of DMA transfers.
Figure 22.20 shows the data alignment in the respective boundary modes in DMA transfers.
Table 22.11 DMA Transfer Access Size and Endian Conversion Mode
Local Bus
Endian
Big endian
Little endian
Data Transfer
Direction
Local bus ↔ PCI bus
Local bus ↔ PCI bus
Access
Size
LW
LW
Endian Conversion Mode
W/LW Boundary Byte Data
Mode (1 to 3)
Boundary Mode
Yes
Yes
Conversion not
required
Conversion not
required
When local bus is big endian
Local bus
PCI bus
Byte data
W/LW
W/LW
W/LW
boundary mode boundary mode 1 boundary mode 2 boundary mode 3
Size = ³¹
0 31
0 31
0 31
0 31
0
=
LW
B0 B1 B2 B3 B3 B2 B1 B0 B3 B2 B1 B0 B2 B3 B0 B1 B0 B1 B2 B3 ₀₀₀₀
When local bus is little endian
Local bus
Size = ³¹
0
LW
B3 B2 B1 B0
PCI bus
31
0
B3 B2 B1 B0
Figure 22.20 Data Alignment at DMA Transfer
=
0000
Rev. 3.0, 04/02, page 913 of 1064