Rainbow Electronics W90N745CDG - Manual (Page 77)

W90N745CD/W90N745CDG
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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 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 REVERSED
1 1 1 REVERSED