
M E M O R Y C O N T R O L L E R
Dynamic Memory Refresh Timer register
236
Hardware Reference NS9215
Register bit
assignment
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D y n a m i c M e m o r y R e f r e s h T i m e r r e g i s t e r
Address: A070 0024
Bits
Access
Mnemonic
Description
D31:15
N/A
Reserved
N/A (do not modify)
D14
R/W
nRP
Sync/Flash reset/power down signal (
dy_pwr_n
)
0
dy_pwr_n
signal low (reset value on
reset_n
)
1
Set
dy_pwr_n
signal high
D13
R/W
Not used
Always write to 0.
D12:09
N/A
Reserved
N/A (do not modify)
D08:07
R/W
SDRAMInit
SDRAM initialization
00
Issue
SDRAM NORMAL
operation command (reset value on
reset_n
)
01
Issue
SDRAM MODE
command
10
Issue
SDRAM PALL
(precharge all) command
11
Issue
SDRAM NOP
(no operation) command
D06
N/A
Reserved
N/A (do not modify)
D05
R/W
Not used
Must write 0.
D04:03
N/A
Reserved
N/A (do not modify)
D02
R/W
SR
Self-refresh request (
SREFREQ
)
0
Normal mode
1
Enter self-refresh mode (reset value on
reset_n
)
By writing 1 to this bit, self-refresh can be entered under software
control. Writing 0 to this bit returns the memory controller to
normal mode.
The self-refresh acknowledge bit in the Status register must be
polled to discover the current operating mode of the memory
controller.
Note:
The memory controller exits from power-on reset with the
self-refresh bit on high. To enter normal functional mode,
set the self-refresh bit low. Writing to this register with the
bit set to high places the register into self-refresh mode.
This functionality allows data to be stored over SDRAM
self-refresh of the ASIC is powered down.
D01
R/W
Not used
Must write 1.
D00
R/W
CE
Dynamic memory clock enable
0
Clock enable if idle devices are deasserted to save power (reset
value on
reset_n
)
1
All clock enables are driven high continuously.
Note:
Clock enable must be high during SDRAM initialization.
Содержание NS9215
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Страница 44: ...P I N O U T 26 5 System clock 44 Hardware Reference NS9215 System clock drawing...
Страница 52: ...P I N O U T 26 5 Power and ground 52 Hardware Reference NS9215...
Страница 80: ...I O C O N T ROL M O D U L E Memory Bus Configuration register 80 Hardware Reference NS9215...
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Страница 516: ...PA CKA GING Processor Dimensions 516 Hardware Reference NS9215...