Filter
Top Products
www.ti.com
3DeviceConfiguration
3.1DeviceConfigurationatDeviceReset
SM320C6455-EP
FIXED-POINTDIGITALSIGNALPROCESSOR
SPRS462B–SEPTEMBER2007–REVISEDJANUARY2008
OntheC6455device,certaindeviceconfigurationslikebootmode,pinmultiplexing,andendianess,are
selectedatdevicereset.Thestatusoftheperipherals(enabled/disabled)isdeterminedafterdevicereset.
Bydefault,theperipheralsontheC6455devicearedisabledandneedtobeenabledbysoftwarebefore
beingused.
Table3-1describestheC6455deviceconfigurationpins.ThelogicleveloftheAEA[19:0],ABA[1:0],and
PCI_ENpinsislatchedatresettodeterminethedeviceconfiguration.Thelogiclevelonthedevice
configurationpinscanbesetbyusingexternalpullup/pulldownresistorsorbyusingsomecontroldevice
(e.g.,FPGA/CPLD)tointelligentlydrivethesepins.Whenusingacontroldevice,careshouldbetakento
ensurethereisnocontentiononthelineswhenthedeviceisoutofreset.Thedeviceconfigurationpins
aresampledduringresetandaredrivenaftertheresetisremoved.Toavoidcontention,thecontroldevice
shouldonlydrivetheEMIFApinswhenRESETSTATislow.
NOTE
Ifaconfigurationpinmustberoutedoutfromthedeviceand3-stated(notdriven),the
internalpullup/pulldown(IPU/IPD)resistorshouldnotbereliedupon;TIrecommendsthe
useofanexternalpullup/pulldownresistor.Formoredetailedinformationon
pullup/pulldownresistorsandsituationswhereexternalpullup/pulldownresistorsare
required,seeSection3.7,Pullup/PulldownResistors.
Table3-1.C6455DeviceConfigurationPins(AEA[19:0],ABA[1:0],andPCI_EN)
CONFIGURATIONIPD/
NO.FUNCTIONALDESCRIPTION
PINIPU
(1)
BootModeSelections(BOOTMODE[3:0]).
Thesepinsselectthebootmodeforthedevice.
0000Noboot(defaultmode)
0001Hostboot(HPI)
0010Reserved
0011Reserved
[N25,0100EMIFA8bitROMboot
L26,
0101MasterI2Cboot
AEA[19:16]IPD
L25,
0110SlaveI2Cboot
P26]
0111Hostboot(PCI)
1000thruSerialRapidI/Obootconfigurations
1111
Ifselectedforboot,thecorrespondingperipheralisautomaticallyenabledafterdevicereset.
Formoredetailedinformationonbootmodes,seeSection2.4,BootSequence.
CFGGP[2:0]pinsmustbesetto000bduringresetforproperoperationofthePCIboot
mode.
EMIFAinputclocksourceselect(AECLKIN_SEL).
0AECLKIN(defaultmode)
AEA15P27IPD
1SYSCLK4(CPU/x)ClockRate.TheSYSCLK4clockrateissoftwareselectable
viatheSoftwarePLL1Controller.Bydefault,SYSCLK4isselectedasCPU/8
clockrate.
(1)IPD=Internalpulldown,IPU=Internalpullup.Formostsystems,a1-kΩresistorcanbeusedtoopposetheIPU/IPD.Formoredetailed
informationonpullup/pulldownresistorsandsituationswhereexternalpullup/pulldownresistorsarerequired,seeSection3.7,
Pullup/PulldownResistors.
SubmitDocumentationFeedbackDeviceConfiguration59