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PRODUCT PREVIEW
Boot
mode
?
Reset
Boot
mode
?
Bootfrom
NANDflash
InternalROM
BootOK?
No
Yes
Bootfrom
UART
Bootfrom
MMC/SD
BootOK?
BootOK?
Yes
No
Invokeloaded
Program
Invoke
OneNAND
No
Yes
3.13PowerManagement
TMS320DM355
DigitalMediaSystem-on-Chip(DMSoC)
SPRS463A–SEPTEMBER2007–REVISEDSEPTEMBER2007
•ARMROMBoot-UARTmode
–Nosupportforafullfirmwareboot.Instead,loadsasecondstageuserbootloader(UBL)viaUART
toARMinternalRAM(AIM)andtransferscontroltotheusersoftware.
–Supportforupto30KBUBL(32KB-~2KBforRBLstack)
ThegeneralbootsequenceisshowninFigure3-6.Formoreinformation,refertotheARMSubsystem
User'sGuide.
Figure3-6.BootModeFunctionalBlockDiagram
Theisdesignedforminimalpowerconsumption.Therearetwocomponentstopowerconsumption:active
powerandleakagepower.Activepoweristhepowerconsumedtoperformworkandscaleswithclock
frequencyandtheamountofcomputationsbeingperformed.Activepowercanbereducedbycontrolling
theclocksinsuchawayastoeitheroperateataclocksettingjusthighenoughtocompletetherequired
operationintherequiredtimelineortorunataclocksettinguntiltheworkiscompleteandthendrastically
cuttheclocks(e.g.toPLLBypassmode)untiladditionalworkmustbeperformed.Leakagepowerisdue
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