W90N745CD Datasheet, PDF (39/422 Pages) Winbond – 16/32-bit ARM microcontroller

W90N745CD/W90N745CDG
Table 6.2.9 and Table 6.2.10
Using little-endian and word access, Program/Data path between register and external memory
WA = Address whose LSB is 0,4,8,C X = Don’t care
nWBE [1-0] / SDQM [1-0] = A means active and U means inactive
Table 6.2.9 Word access write operation with little Endian
ACCESS OPERATION
WRITE OPERATION (CPU REGISTER Î EXTERNAL MEMORY)
XD WIDTH
HALF WORD
BYTE
Bit Number
CPU Reg Data
31 0
ABCD
31 0
ABCD
SA
WA
WA
Bit Number
SD
Bit Number
ED
31 0
AB CD
31 0
ABCD
15 0
15 0
70
70
70
70
CD
AB
D
C
B
A
XA
WA
WA+2
WA
WA+1
WA+2
WA+3
nWBE [1-0] /
SDQM [1-0]
Bit Number
XD
Bit Number
Ext. Mem Data
Timing Sequence
AA
15 0
CD
15 0
CD
1st write
AA
15 0
AB
15 0
AB
2nd write
XA
70
D
70
D
1st write
XA
70
C
70
C
2nd write
XA
70
B
70
B
3rd write
XA
70
A
70
A
4th write
Table 6.2.10 Word access read operation with Little Endian
ACCESS OPERATION
READ OPERATION (CPU REGISTER Í EXTERNAL MEMORY)
XD Width
Half Word
Byte
Bit Number
CPU Reg Data
31 0
ABCD
31 0
ABCD
SA
WA
WA
Bit Number
SD
Bit Number
ED
31 0
AB CD
31 0
XX CD
31 0
AB CD
31 0
XXXD
31 0
ABCD
31 0
XXCD
31 0
XBCD
31 0
ABCD
XA
WA
WA+2
WA
WA+1
WA+2
WA+3
SDQM [1-0]
Bit Number
XD
Bit Number
Ext. Mem Data
Timing Sequence
AA
15 0
CD
15 0
CD
1st write
AA
15 0
AB
15 0
AB
2nd write
XA
70
D
70
D
1st write
XA
70
C
70
C
2nd write
XA
70
B
70
B
3rd write
XA
70
A
70
A
4th write
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