Atmel Evaluation Kit AT91SAM9X25-EK AT91SAM9X25-EK Data Sheet
Product codes
AT91SAM9X25-EK
457
SAM9X25 [DATASHEET]
11054E–ATARM–10-Mar-2014
30.7.1 DDRSDRC Mode Register
Name:
DDRSDRC_MR
Address:
0xFFFFE800
Access:
Read-write
Reset:
See
This register can only be written if the bit WPEN is cleared in
.
• MODE: DDRSDRC Command Mode
This field defines the command issued by the DDRSDRC when the SDRAM device is accessed. This register is used to initialize
the SDRAM device and to activate deep power-down mode.
the SDRAM device and to activate deep power-down mode.
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
–
7
6
5
4
3
2
1
0
–
–
–
–
–
MODE
MODE
Description
000
Normal Mode. Any access to the DDRSDRC will be decoded normally. To activate this mode, command must be followed
by a write to the SDRAM.
by a write to the SDRAM.
001
The DDRSDRC issues a NOP command when the SDRAM device is accessed regardless of the cycle. To activate this
mode, command must be followed by a write to the SDRAM.
mode, command must be followed by a write to the SDRAM.
010
The DDRSDRC issues an “All Banks Precharge” command when the SDRAM device is accessed regardless of the cycle.
To activate this mode, command must be followed by a write to the SDRAM.
To activate this mode, command must be followed by a write to the SDRAM.
011
The DDRSDRC issues a “Load Mode Register” command when the SDRAM device is accessed regardless of the cycle.
To activate this mode, command must be followed by a write to the SDRAM.
To activate this mode, command must be followed by a write to the SDRAM.
100
The DDRSDRC issues an “Auto-Refresh” Command when the SDRAM device is accessed regardless of the cycle.
Previously, an “All Banks Precharge” command must be issued. To activate this mode, command must be followed by a
write to the SDRAM.
Previously, an “All Banks Precharge” command must be issued. To activate this mode, command must be followed by a
write to the SDRAM.
101
The DDRSDRC issues an “Extended Load Mode Register” command when the SDRAM device is accessed regardless of
the cycle. To activate this mode, the “Extended Load Mode Register” command must be followed by a write to the
SDRAM. The write in the SDRAM must be done in the appropriate bank.
the cycle. To activate this mode, the “Extended Load Mode Register” command must be followed by a write to the
SDRAM. The write in the SDRAM must be done in the appropriate bank.
110
Deep power mode: Access to deep power-down mode
111
Reserved