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7.21.3GPIOElectricalData/Timing
GPIx
GPOx
4
3
2
1
SM320C6455-EP
FIXED-POINTDIGITALSIGNALPROCESSOR
SPRS462B–SEPTEMBER2007–REVISEDJANUARY2008
Table7-114.TimingRequirementsforGPIOInputs
(1)(2)
(seeFigure7-78)
-720
-850
A-1000/-1000
NO.UNIT
-1200
MINMAX
1t
w(GPIH)
Pulseduration,GPIxhigh12Pns
2t
w(GPIL)
Pulseduration,GPIxlow12Pns
(1)P=1/CPUclockfrequencyinns.Forexample,whenrunningpartsat1000MHz,useP=1ns.
(2)ThepulsewidthgivenissufficienttogenerateaCPUinterruptoranEDMAevent.However,ifauserwantstohavetheDSPrecognize
theGPIxchangesthroughsoftwarepollingoftheGPIOregister,theGPIxdurationmustbeextendedtoatleast24PtoallowtheDSP
enoughtimetoaccesstheGPIOregisterthroughtheCFGBUS.
Table7-115.SwitchingCharacteristicsOverRecommendedOperatingConditionsforGPIOOutputs
(1)
(seeFigure7-78)
-720
-850
A-1000/-1000
NO.PARAMETERUNIT
-1200
MINMAX
3t
w(GPOH)
Pulseduration,GPOxhigh36P–8
(2)
ns
4t
w(GPOL)
Pulseduration,GPOxlow36P–8
(2)
ns
(1)P=1/CPUclockfrequencyinns.Forexample,whenrunningpartsat1000MHz,useP=1ns.
(2)Thisparametervalueshouldnotbeusedasamaximumperformancespecification.Actualperformanceofback-to-backaccessesofthe
GPIOisdependentuponinternalbusactivity.
Figure7-78.GPIOPortTiming
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