h8s-2158 Renesas Electronics Corporation., h8s-2158 Datasheet - Page 176

• Manufacturer Part Number: h8s-2158
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 6 Bus Controller
6.5.2
Table 6.9 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 6.9
Notes: Undefined
Rev. 3.00 Jan 25, 2006 page 124 of 872
REJ09B0286-0300
Area
8-bit access
space
16-bit access
space
Invalid
Ports or others
Figure 6.4 Access Sizes and Data Alignment Control (16-bit Access Space)
Valid Strobes
Data Buses Used and Valid Strobes
Byte size
Byte size
Word size
Longword
size
Access
Size
Byte
Byte
Word
: Undefined data is output.
: Input state with the input value ignored.
: Used as ports or I/O pins for on-chip peripheral modules, and are not
used as the data bus.
Read/
Write
Read
Write
Read
Write
Read
Write
• Even address
• Odd address
1st bus cycle
2nd bus cycle
Address
—
—
Even
Odd
Even
Odd
—
—
Valid
Strobe
RD
HWR
RD
HWR
LWR
RD
HWR, LWR
D15
Upper data bus
Upper Data Bus
(D15 to D8)
Valid
Valid
Invalid
Valid
Undefined
Valid
Valid
D8 D7
Lower data bus
D0
Lower Data
Bus (D7 to D0)
Ports or others
Ports or others
Invalid
Valid
Undefined
Valid
Valid
Valid