汽車(chē)電子技術(shù)單片機(jī)至第七次課

鐵鐵介 媒介控制(MAC,MediumAccessControl)功邏輯鏈路控制(LLCLogicLinkControl)數(shù)據(jù)幀 標(biāo)準(zhǔn)幀(StandardFrame):11bits擴(kuò)展幀(ExtendedFrame):29bits兩種數(shù)據(jù)幀通過(guò)幀中的位”IDEDataData

1109 擴(kuò)展DataSOFstartofFrame:ArbitrationField(仲裁場(chǎng)11bit:Identifier(標(biāo)識(shí)符 RTR(RemotetransmissionRequest), IDE(identificationextended):IDE(identificationextended):區(qū)分發(fā)送的數(shù)據(jù)幀是擴(kuò)展幀IDE(identificationextended):1bit區(qū)分發(fā)送的數(shù)據(jù)幀是擴(kuò)r(標(biāo)準(zhǔn)幀r1r0(擴(kuò)展幀各1bit保留位必須全部以顯性電DLC(Datalengthcode4bits,數(shù)據(jù)長(zhǎng)度碼DLC=0000b~1000bbytID=CAN0TXIDR0bytID8&0x0FF設(shè)置IDCAN0TXIDR1=bytID&0x0FF;CAN0TXIDR2=CAN0TXIDR3=CAN0TXDSR0=0x11;CAN0TXDSR1=0x12;CAN0TXDSR2=0x13;CAN0TXDSR3=0x14;CAN0TXDSR4=0x15;CAN0TXDSR5=0x16;CAN0TXDSR6=0x17;CAN0TXDSR7=0x18;

CAN0TXDLR //(CRCCyclicRedundancyCheck,

CRC的計(jì)算過(guò)程與除法運(yùn)算類(lèi)位3210值10011應(yīng)答間隙（ACKnowledgeSLOT）

NodeB(接收端 正確地接收到有效的報(bào)文 就會(huì)在應(yīng)答間隙（ACK如果發(fā)送者檢測(cè)到ACKSLOT為隱性位，則表示沒(méi)有節(jié)點(diǎn)填充ACK幀RTR=0:數(shù)據(jù) RTR= 幀沒(méi)有數(shù)據(jù)場(chǎng)D Fi幀幀幀幀的作用DLC幀 處 5種錯(cuò)誤CRC錯(cuò)參考: :2填充錯(cuò)誤出現(xiàn)6過(guò)載界定符8個(gè)隱性位數(shù)據(jù)幀 （數(shù)據(jù)幀 幀幀幀間隔:3總線(xiàn)空閑 隱性電平，無(wú)長(zhǎng)度限制(0亦可ITMIntermission,暫停發(fā)送段幀幀幀 暫停發(fā)送8位9876543210101101101111011011011100000000000位98765432101011011011110110110111IDMR011111111111~~

：f_CANCLK：f_CANCLKf_OSCI或f_Tqf_Tq=f_CANCLK/t_Q=t_Q=1/

位 1+(1+n1)+n21+(1+n1)+n211個(gè)位的時(shí)間=1TSG1包括:段與相位1假設(shè)晶振時(shí)鐘頻率是16Mhz如何設(shè)置，使CAN數(shù)據(jù)傳輸速使f_CANCLK設(shè)置Presccalervalue設(shè)置TSG17TSG2延遲指發(fā)送單元的輸出延遲、總線(xiàn)上信號(hào)的延Time接收單元的輸入延遲。這個(gè)段的時(shí)間為以上各延遲時(shí)當(dāng)信號(hào)邊沿不能被包含于SS段中時(shí)，可在此段進(jìn)行補(bǔ)Phase償。由于各單元以各自獨(dú)立的時(shí)鐘工作，細(xì)微的時(shí)鐘相位緩沖段PhaseSegmentonJumpvoid{CAN0CTL10x80CANCAN0CTL0=0x01; //等待CAN進(jìn)入初始化模式CAN0CTL1_LOOPB=0;//不使用循環(huán)自測(cè)模式CAN0CTL1_LISTEN=0; //1只偵聽(tīng)模式,0NormaloperationCAN0IDAC_IDAM=1;//設(shè)置標(biāo)志符接收模式,4個(gè)16位的過(guò)濾器//選擇時(shí)鐘源//fcanclkCAN0CTL1_CLKSRC=0;//0-選擇時(shí)鐘源為晶振時(shí)鐘1-選擇時(shí)鐘源為總線(xiàn)鐘CAN0BTR0_SJW1同步跳轉(zhuǎn)寬度,12TqclockCAN0BTR0_BRP1波特率預(yù)分頻系數(shù)1Prescalervalue2;CAN0BTR1_SAMP=0;//0:Onesampleperbit.每位采樣一次CAN0BTR1_TSEG_20=7;//Tseg2=8CAN0BTR1_TSEG_10=6; //設(shè)置接收標(biāo)志符寄存器CANIDAR0-CANIDAR7CAN0IDAR0=0x20;//#316->ID:0x64C0 CAN0IDAR1=0x00;//#00E0-->7#0080-->4CAN0IDAR2=0x00;CAN0IDAR3=0x00;CAN0IDAR4=0;CAN0IDAR5=CAN0IDAR6=CAN0IDAR7=CAN0IDMR0=CAN0IDMR1=CAN0IDMR2=

//1-忽略標(biāo)志符接收寄存器中的該CAN0IDMR3 //CAN0IDMR4=0x00;CAN0IDMR5=0x07;CAN0IDMR6=0x00;CAN0IDMR7=0x07;

////CAN0CTL0_INITRQ=0; CAN0RIER_RXFIE //使能接受中斷enablethereceivingCAN0TIER= //發(fā)送中斷disablethetransmit}INT16UuCANOutLoop=BOOLEANMSCAN0Trans(INT16UbytID,INT8U*far{uCANOutLoop= ifuCANOutLoo >=1000}if(CAN0CTL0_SYNCH==0)return //FindanyemptytransmitbytID<<=CAN0TXIDR0=(bytID>>8)&0x0FF;CAN0TXIDR1=bytID&0x0FF;CAN0TXIDR2=0;CAN0TXIDR3=CAN0TXDSR0=*msgout; /*設(shè)置數(shù)據(jù)寄存器，數(shù)組msgout由用戶(hù)設(shè)置*/CAN0TXDSR1=*(msgout+1);CAN0TXDSR2=*(msgout+2);CAN0TXDSR3=*(msgout+3);CAN0TXDSR4=*(msgout+4);CAN0TXDSR5=*(msgout+5);CAN0TXDSR6=*(msgout+6);CAN0TXDSR7=*(msgout+7);CAN0TXDLR=8; /*設(shè)置發(fā)送緩存優(yōu)先級(jí)returnTRUE;}INT8UINT8UinterrutvoidCAN0RECINTINT16Sdata{dwIDF[0]=CAN0RXIDR0