h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 202

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 6 Bus Controller
Table 6.5
Area
8-bit access
space
16-bit access
space (Cannot
be used in the
H8S/2138 Group
or H8S/2134
Group)
Notes: Undefined: Undefined data is output.
6.4.4
8-Bit 2-State Access Space: Figure 6.5 shows the bus timing for an 8-bit 2-state access space.
When an 8-bit access space is accessed, the upper half (D15 to D8) of the data bus is used.
Wait states cannot be inserted.
These group have no lower data bus (D7 to D0) pins or LWR pin. In these group, the upper data
bus (D15 to D8) pins are designated D7 to D0, and the HWR signal pin is designated WR.
Rev. 4.00 Jun 06, 2006 page 148 of 1004
REJ09B0301-0400
Invalid: Input state; input value is ignored.
Port, etc.: Pins are used as port or on-chip supporting module input/output pins, and not as
1. The pin names in these group are D7 to D0.
2. The pin name in these group is WR.
3. There are no lower data bus pins in these group.
Basic Timing
Data Buses Used and Valid Strobes
data bus pins.
Access
Size
Byte
Byte
Word
Read/
Write
Read
Write
Read
Write
Read
Write
Address
—
—
Even
Odd
Even
Odd
—
—
Valid
Strobe
RD
HWR *
RD
HWR
LWR
RD
HWR,
LWR
2
Upper Data Bus
(D15 to D8) *
Valid
Valid
Invalid
Valid
Undefined
Valid
Valid
1
Lower Data Bus
(D7 to D0) *
Port, etc.
Port, etc.
Invalid
Valid
Undefined
Valid
Valid
Valid
3