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Rainbow Electronics W90N740 User Manual

Page 26

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W90N740

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Table 7.2.7 and Table 7.2.8

Using big-endian and byte access, Program/Data path between register and external memory.

BA = Address whose LSB is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F

BAL = Address whose LSB is 0, 2, 4, 6, 8, A, C, E BAU = Address whose LSB is 1, 3, 5, 7, 9, B, D,
F

BA0 = Address whose LSB is 0, 4, 8, C BA1 = Address whose LSB is 1, 5, 9, D

BA2 = Address whose LSB is 2, 6, A, E BA3 = Address whose LSB is 3, 7, B, F

Table7.2.7 Byte access write operation with Big Endian

Access Operation

Write Operation (CPU Register Î External Memory)

XD Width

Word

Half Word

Byte

Bit Number

CPU Reg Data

31 0

ABCD

31 0

ABCD

31 0

ABCD

SA

BA0 BA1 BA2 BA3 BAL BAU BA

Bit Number

SD

31 0

D D D D

31 0

D D D D

31 0

D D D D

31 0

D D D D

31 0

D D D D

31 0

D D D D

31 0

D D D D

Bit Number

ED

31 24

D

23 16

D

15 8

D

7 0

D

15 8

D

7 0

D

7 0

D

XA

BA0 BA0 BA0 BA0 BAL BAL BA

nWBE [3-0] /

SDQM [3-0]

AUUU UAUU UUAU UUUA XXAU XXUA XXXA

Bit Number

XD

31 0

D X X X

31 0

X D X X

31 0

X X D X

31 0

X X X D

15 0

D X

15 0

X D

7 0

D

Bit Number

Ext. Mem Data

31 24

D

23 16

D

15 8

D

7 0

D

15 8

D

7 0

D

7 0

D

Timing Sequence