CHAPTER 4 BUS CONTROL FUNCTION
105
User’s Manual U14359EJ4V0UM
4.5.3 Endian control function
The endian control function can be used to set processing of word data in memory using either the big endian
method or the little endian method for each CS space selected with the chip select signals (CS0 to CS7). Switching of
the endian method is specified using the endian configuration register (BEC).
Caution
In the following areas, the data processing method is fixed to little endian, so the setting of the
BEC register is invalid.
••••
On-chip peripheral I/O area
••••
Internal ROM area
••••
Internal RAM area
••••
Fetch area for external memory
(1) Endian configuration register (BEC)
This register can be read/written in 16-bit units.
Be sure to set bits 15, 13, 11, 9, 7, 5, 3, and 1 to 0. If they are set to 1, the operation is not guaranteed.
Caution
Write to the BEC register after reset, and then do not change the set value.
15
0
BEC
CSn signal
Address
FFFFF068H
After reset
0000H
14
BE70
13
0
12
BE60
11
0
10
BE50
9
0
8
BE40
7
0
6
BE30
5
0
4
BE20
3
0
2
BE10
1
0
0
BE00
CS3
CS2
CS1
CS0
CS4
CS5
CS6
CS7
Bit position
Bit name
Function
Big Endian
Specifies the endian method.
BEn0
Endian control
0
Little endian method
1
Big endian method
14, 12, 10, 8,
6, 4, 2, 0
BEn0
(n = 0 to 7)
Содержание V850E/MA1
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