Rainbow Electronics W90P710CDG User Manual
Page 79
W90P710CD/W90P710CDG
Publication Release Date: September 19, 2006
- 79 -
Revision B2
External I/O Control Registers（EXT0CON – EXT3CON）
The W90P710 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 ADDRESS R/W
DESCRIPTION
RESET
VALUE
EXT0CON
0xFFF0_1018
R/W External I/O 0 control register
0x0000_0000
EXT1CON
0xFFF0_101C
R/W External I/O 1 control register
0x0000_0000
EXT2CON
0xFFF0_1020
R/W External I/O 2 control register
0x0000_0000
EXT3CON
0xFFF0_1024
R/W External I/O 3 control register
0x0000_0000
31
30
29
28
27
26
25
24
BASADDR
23
22
21
20
19
18
17
16
BASADDR SIZE
15
14
13
12
11
10
9
8
ADRS tACC
tCOH
7
6
5
4
3
2
1
0
tACS tCOS
DBWD
BITS
DESCRIPTION
[31:11] BASADDR
Base address pointer of external I/O bank 0~3
The start address of each external I/O bank is calculated as “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.
[18:16] SIZE
The size of the external I/O bank 0~3
SIZE [18:16]
Byte
0 0 0
256K
0 0 1
512K
0 1 0
1M
0 1 1
2M
1 0 0
4M
1 0 1
8M
1 1 0
16M
1 1 1 REVERSED