ADSP-214xx SHARC Processor Hardware Reference
3-131
External Port
frequency change requires self-refresh mode. The DDR2 DDR2 input
core to DDR2 clock ratio change can be made under following condition:
1. The ODT must be turned off.
2. Put the DDR2 DDR2 in precharge power down mode (
DDR2CKE
pin goes low). A minimum of 2 DDR2 clock cycles must occur
after the clock frequency change.
3. The core to DDR2 clock divider is allowed to change only within
the minimum and maximum operating frequency specified for the
particular speed grade. During input clock frequency change,
ODT and
DDR2CKE
must be held at stable low levels.
4. Once the input clock frequency has changed, stable new clocks
must be provided to DRAM before the precharge power down may
be exited.
5. Reset the on-chip DLL and wait until it locks to new frequency.
6. Depending on new the clock frequency, an additional MRS or
EMRS command may needed to appropriately set the writes, laten-
cies and other parameters. During the DLL re-lock period, ODT
must remain off.
7. Before writing to
DDR2CTL0
register, exit the precharge power-down
mode (
DDR2CKE
pin goes high). This ensures the DLL reset via
mode register happens during
DDR2CKE
high.
External Instruction Fetch
The section describes the software programming steps needed for the suc-
cessful operation of external instruction fetch through the external port.
Note only the additional steps for code execution are illustrated. For tim-
ing related settings refer to
“Functional Description” on page 3-7
.
www.BDTIC.com/ADI
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...