HD6417320 RENESAS [Renesas Technology Corp], HD6417320 Datasheet - Page 393

• Manufacturer Part Number: HD6417320
• Description: Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7700 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

9.5
9.5.1
This LSI supports big endian, in which the 0 address is the most significant byte (MSByte) in the
byte data and little endian, in which the 0 address is the least significant byte (LSByte) in the byte
data. Endian is specified on power-on reset by the external pin (MD5). When MD5 pin is low
level on power-on reset, the endian will become big endian and when MD5 pin is high level on
power-on reset, the endian will become little endian.
Three data bus widths (8 bits, 16 bits, and 32 bits) are available for normal memory and byte-
selection SRAM. Two data bus widths (16 bits and 32 bits) are available for SDRAM. Two data
bus widths (8 bits and 16 bits) are available for PCMCIA interface. Data alignment is performed
in accordance with the data bus width of the device and endian. This also means that when
longword data is read from a byte-width device, the read operation must be done four times. In
this LSI, data alignment and conversion of data length is performed automatically between the
respective interfaces.
Tables 9.6 to 9.11 show the relationship between endian, device data width, and access unit.
Table 9.6
Operation
Byte access
at 0
Byte access
at 1
Byte access
at 2
Byte access
at 3
Word access
at 0
Word access
at 2
Longword
access at 0
Operation
Endian/Access Size and Data Alignment
32-Bit External Device/Big Endian Access and Data Alignment
D31 to
D24
Data
7 to 0



Data
15 to 8

Data
31 to 24
D23 to
D16

Data
7 to 0


Data
7 to 0

Data
23 to 16
Data Bus
D15 to
D8


Data
7 to 0


Data
15 to 8
Data
15 to 8
D7 to D0



Data
7 to 0

Data
7 to 0
Data
7 to 0
WE3(BE3),
DQMUU
Assert



Assert

Assert
Rev. 3.00 Jan. 18, 2008 Page 331 of 1458
Section 9
WE2(BE2),
DQMUL

Assert


Assert

Assert
Strobe Signals
Bus State Controller (BSC)
WE1(BE1),
DQMLU


Assert


Assert
Assert
REJ09B0033-0300
WE0(BE0),
DQMLL



Assert

Assert
Assert