Rainbow Electronics W90N740 User Manual
Page 46
W90N740
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EBI Control Register (EBICON)
Register Address R/W
Description
Reset
Value
EBICON
0xFFF0.1000
R/W EBI control register
0x0001.0000
31
30
29
28
27
26
25
24
RESERVED
23
22
21
20
19
18
17
16
RESERVED REFEN
REFMOD
CLKEN
15
14
13
12
11
10
9
8
REFRAT
7
6
5
4
3
2
1
0
REFRAT WAITVT
LITTLE
REFEN [18]: Enable SDRAM refresh cycle for SDRAM bank0 & bank1
This bit set will start the auto-refresh cycle to SDRAM. The refresh rate is according to REFRAT bits.
REFMOD [17]: The refresh mode of SDRAM for SDRAM bank
Defines the refresh mode type of external SDRAM bank
0 = Auto refresh mode
1 = Self refresh mode
CLKEN [16]: Clock enable for SDRAM
Enables the SDRAM clock enable (CKE) control signal
0 = Disable (power down mode)
1 = Enable （Default）
REFRAT [15:3]: Refresh count value for SDRAM
The refresh period is calculated as
fMCLK
value
period
=
The SDRAM Controller automatically provides an auto refresh cycle for every refresh period
programmed into the REFRAT bits when the REFEN bit of each bank is set.