HD64F2357F20V Datasheet, PDF (157/1049 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-chip Microcomputer H8S Family / H8S/2300 Series

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
8-bit access
space
Access
Size
Byte
Read/
Write
Read
Write
Address
—
—
Valid
Strobe
RD
HWR
Upper Data Bus
(D₁₅ to D₈)
Valid
16-bit access Byte Read Even
RD
space
Odd
Valid
Invalid
Write Even
HWR
Valid
Odd
LWR
Hi-Z
Word Read —
RD
Valid
Write —
HWR, LWR Valid
Legend:
Hi-Z: High impedance
Invalid: Input state; input value is ignored.
Lower data bus
(D₇ to D₀)
Invalid
Hi-Z
Invalid
Valid
Hi-Z
Valid
Valid
Valid
Rev.6.00 Oct.28.2004 page 127 of 1016
REJ09B0138-0600H