Renesas ZTAT H8S/2357F, Руководство по оборудованию

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Rev.6.00 Oct.28.2004 page 127 of 1016
REJ09B0138-0600H
6.4.3 Valid Strobes
Table 6-4 shows the data buses used and valid strobes for the access spaces.
In a read, the
RD
signal is valid without discrimination between 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 6-4 Data Buses Used and Valid Strobes
Area
Access
Size Read/
Write
Address
Valid
Strobe Upper Data Bus
(D
15
to D
8
)
Lower data bus
(D
7
to D
0
)
8-bit access Byte Read —
RD
Valid Invalid
space
Write —
HWR
Hi-Z
16-bit access Byte Read Even
RD
Valid Invalid
space
Odd Invalid Valid
Write Even
HWR
Valid Hi-Z
Odd
LWR
Hi-Z Valid
Word Read —
RD
Valid Valid
Write —
HWR
,
LWR
Valid Valid
Legend:
Hi-Z: High impedance
Invalid: Input state; input value is ignored.