标题: ?????????ú????±????÷?è????????A/D±????÷ [打印本页]

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作者: ????    时间: 2004-4-20 18:10     标题: ?????????ú????±????÷?è????????A/D±????÷

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MSP430F1121??16??RISC?á????FLASH???????ú??????????14?????òI/O??????????????????????16???¨?±?÷???????????¨?±??????I/O?????????????±???????üVcc?????????±???üVss???ò????????I/O????????×÷????DAC??????PWM??????

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MSP430F1121?????ú??±????÷???????????????????ú???????????????????????????·±?????±????é?????????¨???í????±????÷?????????????????????ú?????????????·???????????±??±????÷??????????±????????ù??????±????÷?????????????????????????¨???????????????????????¨???¨?÷?ó????????±????÷????????±???????·??????ü?????????¨?ó?????á???????????????????ó??????????????????????????????

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作者: ????    时间: 2004-4-20 18:10

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????1?ù?????ú?ú1??DAC?????·?????·?¨??I/O????????????????×è?????????????????ú?úVout????????Vout=Vin??±????¨??I/O??????????????·?????????±????÷???????????¨??????????????·???(??I/O??????????????)?????ùA/D???????????à????????·?????±??·??????????1?????·???????±±????÷?????????????±?????÷Vout??Vin?????±????????·??????òI/O???????????????±±????÷?????????????±?????÷Vout??Vin?????????????????òI/O??????????????

????·??????????±???·?¨??·?·¨???????????????????¨???±??t?ó???é??±????÷??????×?????????±????÷??????×?????±????ò????I/O???????????±±????÷??????×???·??ú??±????òI/O????????×?????????±????ò?? ??I/O??????×???(??/??????)???????±????????Xt(X??????)????????????A/D×?????????????????????????X1??X2??...??Xi??...??Xn??Xn???????ú??????????±????÷??????×??????¨?????????????±??t?ó??????I/O???????????????????ò?????è?¨????????1???±A/D×????ê???ó????????I/O????????????????????m??

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V(t)=V(1-exp(-t/RC))
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N=X1+X2+????Xn
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Vin(t)=Vin
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Vout(t)=Vin+m(Vcc-Vin)(1-exp(-t/RC))-(N-m)Vin(1-exp(-t/RC)
m(Vcc-Vin)(1-exp(-t/RC))??????????
(N-m)Vin(1-exp(-t/RC)??·???????
?ò????
Vin=Vcc??m/N (1)
???????????°?á??????Vin ?????±??????±????????·?¨Vout?????????¤????????????????A/D×????°??Vout=Vin?????¨??I/O?????????¤??????±????÷??·??ú??????·?×??ó????????????·?A/D×?????

??????(1)??×÷???????í????????A/D×????????í?ü??·?±???????????????Vcc??3.0V????N=3000???ò·?±?????1mV???±m=1245?±?? Vin=1.245V??????N=30000???ò·?±?????0.1mV????m=12456?±???òVin=1.2456V?????ù???????¨????m???·?¨??????????Vin??????±??????±????????(1)???????????????é·???

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作者: ????    时间: 2004-4-20 18:11

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????1?ù?????·?????????????ò????????????????????HT1621×÷?????§?????????÷??P1.0~P1.3????I/O??????HT1621???????á???±?????????????????????·????????????????12??????·?±???????·ü±í??

MSP430F1121??????4K FLASH ?????÷??????±????ò??????·?????×÷???????????÷?????ò???????????????á??·???FLASH?????÷????????????????·???????MSP430F1121 ????????16???¨?±?÷????????????I/O????????????UART??????·????????á??????????PC?ú???????????????????ù?????ò?×???????¨?÷??

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1. MSP430X1XX Family User&#39s Guide 2000
2. TI Application reports/slaa104.pdf

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