Dynamic memory self-refresh exit time register – Digi NS9215 User Manual
Page 240
M E M O R Y C O N T R O L L E R
Dynamic Memory Self-refresh Exit Time register
240
Hardware Reference NS9215
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D y n a m i c M e m o r y S e l f - r e f r e s h E x i t T i m e r e g i s t e r
Address: A070 0038
The Dynamic Memory Self-refresh Exit Time register allows you to program the self-
refresh exit time, t
SREX
. It is recommended that this register be modified during
system initialization, or when there are no current or outstanding transactions. Wait
until the memory controller is idle, then enter low-power or disabled mode. This
value normally is found in SDRAM data sheets as t
SREX
.
Note:
The Dynamic Memory Self-refresh Exit Time register is used for all four
dynamic memory chip selects. The worst case value for all chip selects must
be programmed.
Register
Register bit
assignment
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D y n a m i c M e m o r y L a s t D a t a O u t t o A c t i v e T i m e r e g i s t e r
Address: A070 003C
The Dynamic Memory Last Data Out to Active Time register allows you to program
the last-data-out to active command time, t
APR
. It is recommended that this
register be modified during system initialization, or when there are no current or
outstanding transactions. Wait until the memory controller is idle, then enter low-
power or disabled mode. This value normally is found in SDRAM datasheets as t
APR
.
Note:
The Dynamic Memory Last Data Out to Active Time register is used for all four
dynamic memory chip selects. The worst case value for all chip selects must
be programmed.
13
12
11
10
9
8
7
6
5
4
3
2
1
0
15
14
31
29
28
27
26
25
24
23
22
21
20
19
18
17
16
30
Reserved
Reserved
SREX
Bits
Access
Mnemonic
Description
D31:04
N/A
Reserved
N/A (do not modify)
D03:00
R/W
SREX
Self-refresh exit time (t
SREX
)
0x0–0xE
n+1 clock cycles, where the delay is in
clk_out
cycles.
0xF
16 clock cycles (reset value on
reset_n
)