p2125vps20 Renesas Electronics Corporation., p2125vps20 Datasheet - Page 152

• Manufacturer Part Number: p2125vps20
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 6 Bus Controller (BSC)
(2)
Figure 6.4 illustrates data alignment control for the 16-bit access space. With the 16-bit access
space, the upper data bus (D15 to D8) and lower data bus (D7 to D0) are used for accesses. The
amount of data that can be accessed at one time is one byte or one word, and a longword access is
executed as two word accesses.
In byte access, whether the upper or lower data bus is used is determined by whether the address is
even or odd. The upper data bus is used for an even address, and the lower data bus for an odd
address.
Rev. 1.00 Sep. 21, 2006 Page 114 of 658
REJ09B0310-0100
16-Bit Access Space (Not available in this LSI)
Figure 6.4 Access Sizes and Data Alignment Control (16-bit Access Space)
Byte size
Byte size
Word size
Longword
size
· Even address
· Odd address
1st bus cycle
2nd bus cycle
D15
Upper data bus
D8 D7
Lower data bus
D0