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SDC Functional Description
6-54
ADSP-BF537 Blackfin Processor Hardware Reference
Self-Refresh Exit Command
Leaving self-refresh mode is performed with the self-refresh exit com-
mand, whereby the SDC asserts
SCKE
. Any internal core/DMA access
causes the SDC to perform an exit self-refresh command. The SDC waits
to meet the t
XSR
specification (t
XSR
= t
RAS
+ t
RP
) and then issues an
auto-refresh command. After the auto-refresh command, the SDC waits
for the t
RFC
specification (t
RFC
= t
RAS
+ t
RP
) to be met before executing
the activate command for the transfer that caused the SDRAM to exit
self-refresh mode. Therefore, the latency from when a transfer is received
by the SDC while in self-refresh mode, until the activate command occurs
for that transfer, is:
Time to exit self-refresh:
2
x
(
t
RAS
+
t
RP
)
L
The minimum time between a subsequent self-refresh entry and
the self-refresh exit command is at least t
RAS
cycles. If a self-refresh
entry command is issued during any MemDMA transfer, the SDC
satisfies this core request with the minimum self-refresh period
(t
RAS
).
The application software should ensure that all applicable clock timing
specifications are met before the transfer to SDRAM address space which
causes the controller to exit self-refresh mode. If a transfer occurs to
SDRAM address space when the
SCTLE
bit is cleared, an internal bus error
is generated, and the access does not occur externally, leaving the SDRAM
in self-refresh mode.
For more information, see “Error Detection” on
No Operation Command
The No Operation (NOP) command to the SDRAM has no effect on
operations currently in progress. The command inhibit command is the
same as a NOP command; however, the SDRAM is not chip-selected.
Содержание Blackfin ADSP-BF537
Страница 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...