ADS1255-ADS1256应用24位ADC

第32卷第5期JournalofSouthwestUniversityforNationalities⋅NaturalScienceEditionSept.2006______________________________________________________________________________________________收稿日期2006-06-10作者简介：(1971-).1ADS12552ADS1255文章编号：1003-2843(2006)05-1036-0524A/DADS1255何建,胡焱,周超(618307)摘要：ADS1255TI24Δ∑.ADS1255ADS1255.关键词：A/DΔ∑ADS1255SPI中图分类号:TN911.72文献标识码:A1ADS1255ADS1255(TI)Burr-Brown(ADC)[1-3].(MUX)(BUF)(PGA)Δ-Σ[4-6].ADS1255SSOP-2011)24PGA2)0.00103)234)30kSPS5)ADS1255216)7)8)PGA125.3PGA6422.5,PGA9)(SPI)10)11)5V1.83.6V12)38mW0.4mW.图2ADS1255内部结构图2ADS1255103724A/DADS1255第5期___________________________________________________________________2.1ADS1255的内部结构及工作原理ADS12552Δ-∑SPI.ADS1255312.ADS12550(AINP),1(AINN).AIN0AIN1AINCOMAINCOM.ADS12553(SDCS)ADCONSDCS0SDCS1.ADS1255SDCSMUX0.5uA2uA10uA(ISDC)3(AINPAINN)ISDC(2RMUXRRES)(RRES0)(ISDC2RMUX)ADS1255ADS1255ADS1255.ADS1255..10MΩ80MΩ.STATUSBUFFER.ADS1255ADCONPGA0PGA1PGA2PGA64.ADS1255Δ-∑.Δ-∑...ADS1255(SCLKDINDOUTCS)SPI.ADS1255SPI()ADS1255.CS.SPISCLKDINDOUTSCLK.DINSCLKADS1255SCLKDOUTSCLKADS1255SCLK.DINDOUTRDATACDOUT.4SPI.ADS12552I/OD0D1I/OIODO.ADCONCLK0CLK1fCLKINfCLKIN/2fCLKIN/4.ADCON.IO.34SPI第32卷1038西南民族大学学报·自然科学版___________________________________________________________________ADS1255.PCBADS1255.7.68M(fCLKIN7.68M).2.2ADS1255的主要寄存器功能ADS125511PGAI/O.1:STATUSMUXADADCONDRATE.STATUS(00H)X1H.ID.ORDER0()1.ACAL0()1.BUFFER0()1.DRDYDRDYDRDY.MUX(01H)01H.PSEL1PSEL00000AIN0()0001AIN1NSEL1NSEL00000AIN00001AIN1().ADADCON(02H)20H.0.CLK1CLK00001fCLKIN()10fCLKIN/211=fCLKIN/4.SDCS1SDCS000()010.5uA102uA1110uA.PGA2PGA00001()00120104011810016101321106411164.DRATE(03H)F0H.DIR7DIR01111000030kSPS()1110000015kSPS000100115SPS000000112.5SPS.表1ADS1256主要寄存器状态ADDRESSREGISTERRESETVALUEBIT7BIT6BIT5BIT4BIT3BIT2BIT1BIT000hSTATUSx1HID3ID2ID1ID0ORDERACALBUFENDRDY01hMUX01HPSEL3PSEL2PSEL1PSEL0NSEL3NSEL2NSEL1NSEL002hADCON20H0CLK1CLK0SDCS1SDCS0PGA2PGA1PGA003hDRATEF0HDR7DR6DR5DR4DR3DR2DR1DR03ADS12553.1ADS1255的硬件设计ADS1255A/D.A/DADS1255.5ADC.VREFNVREFP()AVDDADS1255.5RC..103924A/DADS1255第5期___________________________________________________________________ADS1255(AGND)(DGND).D0D1.RESET/SYNCPDWN(DVDD).5ADS1255.3.2ADS1255的应用程序ADS1255.ADS1255CS.ADS1255RESET.ADS1255.STATUSMUXADADCONDRATE..ADS1255voidmain(void){union{longrlong;struct{unsignedcharhbyte;//Highbyteunsignedcharmbyte;//Middlebyteunsignedcharlbyte;//Lowbyteunsignedcharzbyte;//Zerobyte}bytes;}adc_result;ADS1255_RESET=0;ADS1255delay();ADS1255_RESET=1;ADS1255_CS=0;InitADS1255()ADS1255_Write_Byte(CMD_SELFCAL);while(ADS1255_DRDY==1);while(ADS1255_DRDY==0);ADS1255_Write_Byte(CMD_RDATA);adc_result.bytes.hbyte=ADS1255_Read_Byte();adc_result.bytes.mbyte=ADS1255_Read_Byte();adc_result.bytes.lbyte=ADS1255_Read_Byte();printf(\n%08.4fmV,sliding_filter((float)adc_result.rlong/4.0*5000.00/0x7fffffff));}5ADS1255第32卷1040西南民族大学学报·自然科学版___________________________________________________________________4ADS12551)ADS1255AGNDDGNDAGNDDGNDADS1255.2)ADS1255020uF7.68M18pF.3).4)ADS1255VREFVREFPVREFN05V2.5V...5)ADS1255DRDY.参考文献：[1].[M].:,1997.[2].KeilCx51V7.0uVision2[M].:,2004.[3].C[M].:,2003.[4].[M].:,2006.[5].[M].:,2004.[6].51C[M].:,2006.24-BitA/DconverterADS1255andit’sapplicationHEJian,HUYan,ZHOUChao(CivilAviationFlightUniversityofChinaGuanghan618307,P.R.C.)AbstractADS1255islow-power-dissipation,high-resolution,24-bit,andΔ-∑analog-to-digitalconverter,providedbyTexasInstruments,whichintegrateinputmultiplexer,analoginputbuffer,programmablegainamplifierandprogrammabledigitalfilter.Thisarticleintroducesitsprincipalfeatures,operationalprinciple,typicalexampleofapplicationandapplicationprogram,andprovidestheprincipalpointsofuseanddesignexperience.Keywords:A/Dconverter;delta-sigma;ADS1255;samplingrate;serialperipheralinterface