ADSP-214xx SHARC Processor Hardware Reference
3-49
External Port
It should be noted that the DDR2 DLL acts as an interface for only the
signals mentioned above and the clock output (
DDR2_CLK
) to the DDR2, it
does not operate on the
DDR2_ADDR
,
DDR_CS
and command lines (
DDR2_RAS
,
DDR2_CAS
,
DDR2_WE
).
During a memory read, the data from the DDR2 memory (SSTL-18 level)
is converted to the core voltage logic level inside the DDR2 memory I/O
pads. This is captured by the DDR2 DLL using precise delays on the data
strobe (
DDR2_DQS
) line in accordance with the JEDEC specification and
provided to the controller. During a memory write, the data strobe
(
DDR2_DQS1-0
) signal to the DDR2 is delayed by a fixed amount. Note
there are stringent timing requirements between the DDR2 DLL and the
controller.
The DDR2 DLL controls the setting of the delay for the data capture. The
delay elements and DLL in the block are sensitive to process, voltage and
temperature variations as well as to the operating frequency.
The DDR2 controller enables either the read or the write path in the
memory I/O. Read data is sent by the DDR2 DRAM on both the rising
Figure 3-11. DDR2 Controller
ADSP-2146x
DDR2
MEMORY
CONTROLLER
DLL0
ADDRESS/
COMMAND
DDR2
DRAM
MEMORY
DLL1
I/O0
I/O1
DQ7-0/
DQS0
DQ15-8/
DQS1
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Содержание SHARC ADSP-214 Series
Страница 60: ...Contents lx ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 72: ...Notation Conventions lxxii ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 130: ...Programming Model 2 52 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 264: ...Programming Models 3 134 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 290: ...Programming Model 4 26 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 296: ...Programming Model 5 6 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 396: ...Effect Latency 7 28 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 520: ...Programming Model 10 62 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 616: ...Debug Features 14 22 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 656: ...Programming Model 15 40 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 714: ...Programming Model 19 10 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1132: ...Register Listing A 306 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1192: ...Index I 34 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...