AT91RM9200-CI-002 Atmel, AT91RM9200-CI-002 Datasheet - Page 203

• Manufacturer Part Number: AT91RM9200-CI-002
• Description: IC ARM9 MCU 256 BGA
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91RM9200-CI-002

• Core Processor: ARM9
• Core Size: 16/32-Bit
• Speed: 180MHz
• Connectivity: EBI/EMI, Ethernet, I²C, MMC, SPI, SSC, UART/USART, USB
• Peripherals: POR
• Number Of I /o: 122
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: ROM
• Ram Size: 48K x 8
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 256-BGA
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -

19.6.5
19.6.5.1
Figure 19-7. Self-refresh Mode Behavior
1768I–ATARM–09-Jul-09
SDRAMC_SRR
SDCKE
A[12:0]
SDWE
SDCK
SDCS
Write
RAS
CAS
Power Management
Self-refresh Mode
SRCB = 1
Self-refresh mode is used in power-down mode, i.e., when no access to the SDRAM device is
possible. In this case, power consumption is very low. The mode is activated by programming
the self-refresh command bit (SRCB) in SDRAMC_SRR. In self-refresh mode, the SDRAM
device retains data without external clocking and provides its own internal clocking, thus per-
forming its own auto-refresh cycles. All the inputs to the SDRAM device become “don’t care”
except SDCKE, which remains low. As soon as the SDRAM device is selected, the SDRAM
Controller provides a sequence of commands and exits self-refresh mode, so the self-refresh
command bit is disabled.
To re-activate this mode, the self-refresh command bit must be re-programmed.
The SDRAM device must remain in self-refresh mode for a minimum period of t
remain in self-refresh mode for an indefinite period. This is described in
Self Refresh Mode
to the SDRAM Controller
Access Request
AT91RM9200
T
Figure 19-7
XSR
= 3
RAS
below.
Row
and may
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