Valid Strobes - Renesas H8S Family Hardware Manual

6.5.2

Valid Strobes

Table 6.13 shows the data buses used and valid strobes for each access space.
In a read, the RD signal is valid for both the upper and lower halves of the data bus. In a write, the
HWR signal is valid for the upper half of the data bus, and the LWR signal for the lower half.
Table 6.13 Data Buses Used and Valid Strobes
Access
Size
Area
8-bit access
Byte
space
8-bit access
Byte
space
(in address-
data multiplex
extended
mode)
16-bit access
Byte
space
Word
[Legend]
Undefined: Undefined data is output.
Invalid: Input state with the input value ignored.
Ports or others: Used as ports or I/O pins for on-chip peripheral modules, and are not used as the
data bus.
Read/
Write
Address
Read —
Write —
Read —
Write —
Read Even
Odd
Write Even
Odd
Read —
Write —
Upper Data Bus
Valid (D15 to D8/
Strobe AD15 to AD8)
RD
Valid
HWR
RD
Ports or others
HWR
RD
Valid
Invalid
HWR
Valid
LWR
Undefined
RD
Valid
HWR, LWR
Rev. 1.00 Mar. 12, 2008 Page 127 of 1178
Section 6 Bus Controller (BSC)
Lower Data
Bus (D7 to
D0/AD7 to
AD0)
Ports or others
Valid
Invalid
Valid
Undefined
Valid
Valid
REJ09B0403-0100