Avoiding_Pitfalls_with_Bootloaders.pdf

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1、AvoidingPitfallsinBootloaders–ESC2011AvoidingPitfallswithBootloadersAvoidingPitfallsinBootloaders–ESC2011Agenda•WhatisaBootloader?•Definition•FreeandCommercialBootloaders•BenefitsofusingaBootloader•Upgradability•Fastproductionprogramming•SettingupabootloaderintheEmbeddedWorkbench•Debuggingbootloader

2、s•Safeandsecurebootloaders•ExampleofabootloaderAvoidingPitfallsinBootloaders–ESC2011Whatisabootloader?•AbootloaderisapieceofcodethatallowsyoutoupdatethefirmwareofyourMCU•Althoughthebootloaderupdatestheapplicationfirmware,itisdifficulttoupdatethebootloaderitselfinthefield,soitisimportanttogetitrightt

3、hefirsttime•ItcaneithercheckfornewfirmwareeverytimetheMCUresetsorwhentheMCUresetsandacertainbuttononthephysicaldeviceispressed•Youcanwriteyourownbootloaderoryoucanpurchaseoneofseveralcommerciallyavailablebootloaders•Commerciallyavailablebootloaderscantakethehassleoutofwritinganddebuggingyourownbootl

4、oaderAvoidingPitfallsinBootloaders–ESC2011BenefitsofusingaBootloader•AsfirmwareforMCUsbecomesmorecomplexandhasaddedfunctionality,thepotentialfordefectstoexistinthecodeexponentiates–itisthereforewisetohaveamechanismtoupdatethefirmwareasdefectsarefound•Itgivesyoutheflexibilitytodoaincrementalrolloutof

5、functionalityofyourproduct•Intheolddays,codehadtobeperfect(orascloseaspossible)beforeyoubeganproduction•Nowcustomershavecometoacceptfirmwareupdatesoftheirdevicesaspartoftheprocess•DueinparttotheproliferationofFlashmemorydevices•Itcanbeusedasamass-programmingtoolontheproductionline•Itcansaveyouthehea

6、dacheofaproductrecall!AvoidingPitfallsinBootloaders–ESC2011Typicalbootloaderstartup•DeviceReset•Checkconditional•Iftrue,executeselfprogramming•Iffalse,executemainprogramAvoidingPitfallsinBootloaders–ESC2011ExampleBootloadermemorymap•Bootloaderandappsitsidebysideinflasharray•Bootloaderexecutesat0x800

7、00000andwillcontinuetoexecutedependingonpinconfiguration•OtherwisetheBootloaderjumpstoapplication@0x80002000AvoidingPitfallsinBootloaders–ESC2011SettingupabootloaderintheEW•Thepragmaticsofdoingabootlo