upd70f3402 Renesas Electronics Corporation., upd70f3402 Datasheet - Page 213

• Manufacturer Part Number: upd70f3402
• Description: 32-/16-bit Single-chip Microcontroller With Can Interface
• Manufacturer: Renesas Electronics Corporation.

5.4.3 Access by bus size
The V850E/RS1 accesses the on-chip peripheral I/O and external memory in 8-bit, 16-bit, or 32-bit
units. The bus size is as follows.
•
•
The operation when each of the above is accessed is described below. All data is accessed starting
from the lower side.
The V850E/RS1 supports only the Little-Endian format.
(1)
The bus size of the on-chip peripheral I/O is fixed to 16 bits.
The bus size of the external memory is selectable from 8 bits or 16 bits (by using the BSC register).
Byte access (8 bits)
(a) 16-bit data bus width
(b) 8-bit data bus width
<1> Access to even address (2n)
<1> Access to even address (2n)
Byte data
Byte data
7
0
7
0
31
000BH
0007H
0003H
15
8
7
0
7
0
data bus
data bus
External
External
Figure 5-3: Little-Endian Address in Word
User’s Manual U16702EE3V2UD00
2n
2n
24 23
Address
Address
Chapter 5 Bus Control Function
000AH
0006H
0002H
16 17
<2> Access to odd address (2n + 1)
<2> Access to odd address (2n + 1)
0009H
0005H
0001H
Byte data
Byte data
7
0
7
0
8 7
15
0008H
0004H
0000H
7
0
8
7
0
data bus
data bus
External
External
2n + 1
2n + 1
Address
Address
0
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