W90N745CD/W90N745CDG
External I/O Control Registers（EXT0CON – EXT3CON）
The W90N745 supports an external device control without glue logic. It is very cost effective because
address decoding and control signals timing logic are not needed. Using these control registers you can
configure special external I/O devices for providing the low cost external devices control solution.
REGISTER
EXT0CON
EXT1CON
EXT2CON
EXT3CON
ADDRESS
R/W
DESCRIPTION
RESET VALUE
0x0000_0000
0x0000_0000
0x0000_0000
0x0000_0000
R/W External I/O 0 control register
R/W External I/O 1 control register
R/W External I/O 2 control register
R/W External I/O 3 control register
0xFFF0_1018
0xFFF0_101C
0xFFF0_1020
0xFFF0_1024
31
23
30
22
29
21
28
BASADDR
27
19
11
26
18
10
2
25
17
24
16
20
12
4
BASADDR
13
SIZE
9
15
ADRS
7
14
8
0
tACC
tCOH
1
6
5
3
tACS
tCOS
DBWD
BITS
DESCRIPTION
Base address pointer of external I/O bank 0~3
The start address of each external I/O bank is calculated as “BASADDR”
[31:11] BASADDR base pointer << 18.
Each external I/O bank base address pointer together with the “SIZE” bits
constitutes the whole address range of each external I/O bank.
The size of the external I/O bank 0~3
SIZE [18:16]
Byte
256K
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
512K
1M
[18:16]
SIZE
2M
4M
8M
REVERSED
REVERSED
- 72 -
WINBOND [ WINBOND ]
