HD64F2636F20 Datasheet, PDF (219/1512 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

H8S/2639, H8S/2638, H8S/2636,
H8S/2630, H8S/2635 Group
Section 7 Bus Controller
7.4.3 Valid Strobes
Table 7-4 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 7-4 Data Buses Used and Valid Strobes
Area
Access Read/
Valid
Size Write Address Strobe
Upper Data Bus
(D15 to D8)
8-bit access Byte
space
Read —
Write —
RD
HWR
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
Note: 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
REJ09B0103-0800 Rev. 8.00
May 28, 2010
Page 169 of 1458