Rainbow Electronics W90P710CDG User Manual
Page 44
W90P710CD/W90P710CDG
- 44 -
Table 6.2.11 and Table 6.2.12
Using little-endian and half-word access, Program/Data path between register and external memory.
HA = Address whose LSB is 0,2,4,6,8,A,C,E
HAL = Address whose LSB is 0,4,8,C
HAU = Address whose LSB is 2,6,A,E
X = Don’t care
nWBE [3-0] / SDQM [3-0] = A means active and U means inactive
Table6.2.11 Half-word access write operation with little 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
HAL HAU HA
HA
Bit Number
SD
31 0
CD CD
31 0
CD CD
31 0
CD CD
31 0
CD CD
31 0
CD CD
Bit Number
ED
31 0
CD CD
31 0
CD CD
31 0
CD CD
7 0
D
7 0
C
XA
HAL HAL HA HA HA+1
nWBE [3-0] /
SDQM [3-0]
UUAA AAUU XXAA XXXA XXXA
Bit Number
XD
31 0
CD CD
31 0
CD CD
15 0
CD
7 0
D
7 0
C
Bit Number
Ext. Mem Data
15 0
CD
31 16
CD
15 0
CD
7 0
D
7 0
C
Timing Sequence
1st write
2nd write
Table6.2.12 Half-word access read operation with Little Endian
Access Operation
Read Operation (CPU Register Í External Memory)
XD Width
Word
Half Word
Byte
Bit Number
CPU Reg Data
15 0
CD
15 0
AB
15 0
CD
15 0
CD
SA
HAL HAU HA
HA
Bit Number
SD
15 0
CD
15 0
AB
15 0
CD
15 0
CD
Bit Number
ED
15 0
CD
15 0
AB
15 0
CD
15 0
XD
15 0
CD
XA
HAL HAL HA HA HA+1
SDQM [3-0]
UUAA
AAUU
XXAA
XXXA
XXXA
Bit Number
XD
31 0
AB CD
31 0
AB CD
15 0
CD
7 0
D
7 0
C
Bit Number
Ext. Mem Data
31 0
ABCD
15 0
CD
7 0
D
7 0
C
Timing Sequence
1st read
2nd read