Figure 22.20 Data Alignment At Dma Transfer; Table 22.11 Dma Transfer Access Size And Endian Conversion Mode - Hitachi SH7751 Hardware Manual

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 Data Transfer
Endian Direction
Big endian Local bus
Little endian Local bus
When local bus is big endian
Local bus
31
Size =
B0 B1 B2 B3
LW
When local bus is little endian
Local bus
31
Size =
B3 B2 B1 B0
LW

PCI bus

PCI bus
Byte data
boundary mode boundary mode 1
0 31 0 31
B3 B2 B1 B0 B3 B2 B1 B0
0

Figure 22.20 Data Alignment at DMA Transfer

Endian Conversion Mode
Access W/LW Boundary
Size Mode (1 to 3)
LW Yes
LW Conversion not
required
PCI bus
W/LW W/LW
boundary mode 2
0 31
B2 B3 B0 B1
PCI bus
31
B3 B2 B1 B0
Byte Data
Boundary Mode
Yes
Conversion not
required
W/LW
boundary mode 3
0 31
B0 B1 B2 B3
0
Rev. 3.0, 04/02, page 913 of 1064
0
=
0000
=
0000