MPC5604B的CAN总线通信

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/* main.c: FlexCAN program */

/* Description: Transmit one message from FlexCAN 0 buf. 0 to FlexCAN C buf. 1

（从 FlexCAN 0 buf. 0 传递一个消息到FlexCAN C buf. 1）*/  



/* Rev 0.1 Jan 16, 2006 S.Mihalik, Copyright Freescale, 2006. All Rights Reserved */







/* Rev 0.2 Jun 6 2006 SM - changed Flexcan A to C & enabled 64 msg buffers */



/* Rev 0.3 Jun 15 2006 SM - 1. Made globals uninitialized */

/*                          2. RecieveMsg function:  read CANx_TIMER, removed setting buffer's CODE*/

/*                          3. added idle loop code for smoother Nexus trace */

/*                          4. modified for newer Freescale header files (r 16) */



/* Rev 0.4 Aug 11 2006 SM - Removed redundant CAN_A.MCR init */



/* Rev 0.5 Jan 31 2007 SM - Removed other redundant CAN_C.MCR init */



/* Rev 0.6 Mar 08 2007 SM - Corrected init of MBs- cleared 64 MBs, instead of 63 */



/* Rev 0.7 Jul 20 2007 SM - Changes for MPC5510 */



/* Rev 0.8 May 15 2008 SM - Changes for new header file symbols */



/* Rev 0.9 May 22 2009 SM - Changes for MPC56xxB/P/S */



/* Rev 1.0 Jul 10 2009 SM - Simplified, cleared CAN Msg Buf flag by writing to reg */

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/*   not bit, increased Tx pads slew rate(转换率), changed RxCODE, RxLENGTH, dummy data（虚拟数据） types*/

/*   & init receiving CAN first to allow CAN bus sync time before receiving 1st msg*/

/* Rev 1.1 Mar 14 2010 SM - modified initModesAndClock, updated header file */

/*  NOTE!! structure canbuf_t in header file modified to allow byte addressing*/

/*Chapter 22*/

#include "MPC5604B_M27V.h" /* Use proper include file */



uint32_t  RxCODE;              /* Received message buffer code */

uint32_t  RxID;                 /* Received message ID */

uint32_t  RxLENGTH;            /* Recieved message number of data bytes */

uint8_t   RxDATA[8];            /* Received message data string*/

uint32_t  RxTIMESTAMP;          /* Received message time */    

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void initModesAndClks(void)   /*系统初始化*/

{

  ME.MER.R = 0x0000001D;          /* Enable DRUN, RUN0, SAFE, RESET modes */

                                  /* Initialize PLL before turning it on: (初始化锁相环)*/

/* Use 1 of the next 2 lines depending on crystal frequency: */

//锁相环时钟没问题

  CGM.FMPLL_CR.R = 0x02400100;     

  //0x02400100                   /* 8 MHz xtal: Set PLL0 to 64 MHz */  

  /*CGM.FMPLL_CR.R = 0x12400100;*/  /* 40 MHz xtal: Set PLL0 to 64 MHz */   

  ME.RUN[0].R = 0x001F0074;       /* RUN0 cfg: 16MHzIRCON,OSC0ON,PLL0ON,syclk=PLL */





//  ME.DRUN.R=0x001F0010;





// ME.RUNPC[0].R = 0x000000FE;           /* Peri. Cfg. 1 settings: only run in RUN0 mode */

  ME.RUNPC[0].R = 0x00000010;

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/*要什么功能就在PCTL中配置相应的序号*/

/*选择FlexCAN0和FlexCAN1控制*/

  ME.PCTL[16].R = 0x01;           /* P143   MPC56xxB/P/S FlexCAN0: select ME.RUNPC[1] */       

  //要和RUNPC保持一致

  ME.PCTL[17].R = 0x01;           /* MPC56xxB/S FlexCAN1:  select ME.RUNPC[1] */       

/*选择SIUL控制*/

  ME.PCTL[68].R = 0x01;           /* MPC56xxB/S SIUL:  select ME.RUNPC[1] */       

/*此处未进行端口引脚配置*/



//  ME.PCTL[96].R=0x00;

                                  /* Mode Transition to enter RUN0 mode: */

  ME.MCTL.R = 0x40005AF0;         /* Enter RUN0 Mode & Key */

  ME.MCTL.R = 0x4000A50F;         /* Enter RUN0 Mode & Inverted Key */  

  while (ME.GS.B.S_MTRANS) {}     /* Wait for mode transition to complete */   

                                  /* Note: could wait here using timer and/or I_TC IRQ */

  while(ME.GS.B.S_CURRENTMODE != 4) {} /* Verify RUN0 is the current mode */

}

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void initPeriClkGen(void)    /*??*/

//??????????

{

  CGM.SC_DC[1].R = 0x80;     /* MPC56xxB/S: Enable peri set 2 sysclk divided by 1 */







  CGM.OC_EN.R= 1;

  CGM.OCDS_SC.R= 0x22000000;







}

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void disableWatchdog(void)

{

  SWT.SR.R = 0x0000c520;     /* Write keys to clear soft lock bit */

  SWT.SR.R = 0x0000d928;

  SWT.CR.R = 0x8000010A;     /* Clear watchdog enable (WEN) */

}        

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void initCAN_1 (void)      /*初始化CAN_1*/

{

  uint8_t   i;



  CAN_1.MCR.R = 0x5000003F;       /* Put in Freeze Mode & enable all 64 msg bufs *//*Module Configuration Register----MCR 模式配置寄存器*/

  CAN_1.CR.R = 0x04DB2006;        /* Configure for 8MHz OSC, 100KHz bit time *//*Control Register---CR 控制寄存器*/

  //0x04DB0006

  for (i=0; i<64; i++)

  {

    CAN_1.BUF[i].CS.B.CODE = 0;   /* Inactivate all message buffers */     /*Message Buffer--64个信息缓冲寄存器*/

  } 

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 /*P433*/









  CAN_1.IMRL.B.BUF04M=1;











  CAN_1.BUF[4].CS.B.IDE = 0;      /* MB 4 will look for a standard ID */       /*IDE=0表示Frame format(帧格式) is standard*/

  CAN_1.BUF[4].ID.B.STD_ID = 555; /* MB 4 will look for ID = 555 */            /*ID(帧标识符)*/

  CAN_1.BUF[4].CS.B.CODE = 4;     /* MB 4 set to RX EMPTY */                   /*CODE=0x0100表示EMPTY: MB is active and empty.*/

//  CAN_1.RXGMASK.R = 0x1FFFFF10;   /* Global acceptance mask */                 /*Rx Global Mask Register---RXGMASK*/

  SIU.PCR[42].R = 0x0624;         /* MPC56xxB: Config port C10 as CAN1TX, open drain */

  SIU.PCR[35].R = 0x0103;         /* MPC56xxB: Configure port C3 as CAN1RX */      /*CAN_1的收发送*/

  SIU.PSMI[0].R = 0x00;           /* MPC56xxB: Select PCR 35 for CAN1RX Input */   /*P346*//*因为可以作为CAN1Rx的引脚有三个（PC3 PC11 PF15）这里选择PC3以后，要注释 SIU.PSMI[0].R = 0x00;表明选择的是PC3*/

  CAN_1.MCR.R = 0x0000003F;       /* Negate FlexCAN 1 halt state for  64 MB */

}

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oid initCAN_0 (void)     /*初始化CAN_0*/

{

  uint8_t   i;



  CAN_0.MCR.R = 0x5000003F;       /* Put in Freeze Mode & enable all 64 msg bufs */   /*Freeze Mode(It is enabled when the FRZ bit in the MCR is asserted.)*/







  CAN_0.CR.R = 0x04DB0006;        /* Configure for 8MHz OSC, 100KHz bit time */

  /*怎么配置波特率*/





  for (i=0; i<64; i++)

  {

    CAN_0.BUF[i].CS.B.CODE = 0;   /* Inactivate all message buffers */

  } 

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CAN_0.IMRL.B.BUF00M=1;

  CAN_0.BUF[0].CS.B.IDE = 0;           /* Use standard ID length */  /*IDE=0表示Frame format(帧格式) is standard*/

  CAN_0.BUF[0].ID.B.STD_ID = 555;      /* Transmit ID is 555 */    /*ID(帧标识符)*/

  CAN_0.BUF[0].CS.B.RTR = 0;           /* Data frame, not remote Tx request frame */  /*RTR=0表示Indicates the current MB has a Data Frame to be transmitted(表明当前信息缓冲寄存器将要发送)*/ /*RTR=Remote Transmission Request（远程发送请求）*/

//  CAN_0.RXGMASK.R = 0x1FFFFFFF;  





  CAN_0.BUF[0].CS.B.CODE = 8;     /* Message Buffer 0 set to TX INACTIVE */    /*CODE=0x1000表示INACTIVE: MB does not participate in the arbitration process.*/

  SIU.PCR[16].R = 0x0624;         /* MPC56xxB: Config port B0 as CAN0TX, open drain */

  SIU.PCR[17].R = 0x0103;        /* MPC56xxB: Configure port B1 as CAN0RX */    /*CAN_0的收发送*/

  CAN_0.MCR.R = 0x0000003F;       /* Negate FlexCAN 0 halt state for 64 MB */

}

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/*发送端配置相对简单(或许在信息发送函数中进行了设置)，只对TX设置为Inactive，而接收端设置比较复杂，比如帧和MB的设置*/

void TransmitMsg (void)     /*发送信息函数*/

{

  uint8_t        i;

                                   /* Assumption:  Message buffer CODE is INACTIVE */

  const uint8_t TxData[] = {"Hello"};  /* Transmit string*/  

  CAN_0.BUF[0].CS.B.IDE = 0;           /* Use standard ID length */  /*IDE=0表示Frame format(帧格式) is standard*/

  CAN_0.BUF[0].ID.B.STD_ID = 555;      /* Transmit ID is 555 */    /*ID(帧标识符)*/

  CAN_0.BUF[0].CS.B.RTR = 0;           /* Data frame, not remote Tx request frame */  /*RTR=0表示Indicates the current MB has a Data Frame to be transmitted(表明当前信息缓冲寄存器将要发送)*/ /*RTR=Remote Transmission Request（远程发送请求）*/

  CAN_0.BUF[0].CS.B.LENGTH = sizeof(TxData) -1 ; /* # bytes to transmit w/o null */

  for (i=0; i<sizeof(TxData); i++)

  {

    CAN_0.BUF[0].DATA.B[i] = TxData[i];      /* Data to be transmitted */  /*DATA表示数据段*/

  }

  CAN_0.BUF[0].CS.B.SRR = 1;           /* Tx frame (not req'd for standard frame)*/  /*SRR=1表示 Recessive value is compulsory for transmission in Extended Format frames（在扩展帧格式下隐形值被强制发送）*/

  CAN_0.BUF[0].CS.B.CODE =0xC;         /* Activate msg. buf. to transmit data frame */ /*RTR=0且CODE=1时Transmit data frame unconditionally once. After transmission, the

MB automatically returns to the INACTIVE state.（发送结束后，MB自动返回到非活跃状态）*/

}

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/*发送CAN_0选择缓冲寄存器BUF[0]，接收CAN_1选择缓冲寄存器BUF[1]*/

void RecieveMsg (void)      /*接收信息函数*/

{  

  uint8_t j;

  uint32_t dummy;



  while (CAN_1.IFRL.B.BUF04I == 0) {}; /* Wait for CAN 1 MB 4 flag */  /*等待标志位*/

  RxCODE   = CAN_1.BUF[4].CS.B.CODE;    /* Read CODE, ID, LENGTH, DATA, TIMESTAMP(读取CAN_1的CODE和ID以及Length，Data，Timestamp等参数) */

  RxID     = CAN_1.BUF[4].ID.B.STD_ID;

  RxLENGTH = CAN_1.BUF[4].CS.B.LENGTH;

  for (j=0; j<RxLENGTH; j++)

  {

    RxDATA[j] = CAN_1.BUF[4].DATA.B[j];

  }

  RxTIMESTAMP = CAN_1.BUF[4].CS.B.TIMESTAMP;

  dummy = CAN_1.TIMER.R;                /* Read TIMER to unlock message buffers */   

  CAN_1.IFRL.R = 0x00000010;            /* Clear CAN 1 MB 4 flag */

}

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//void delay_ms(int x)

//{

//        int a,b;

//        for(a=x;a>0;a--)

//                for(b=16000;b>0;b--) ;

//}







void main(void)

{



  volatile uint32_t IdleCtr = 0;





//  delay_ms(1000);



  initModesAndClks();      /* Initialize mode entries */

  initPeriClkGen();        /* Initialize peripheral clock generation for DSPIs */

  disableWatchdog();       /* Disable watchdog */

  initCAN_1();             /* Initialize FLEXCAN 1 & one of its buffers for receive*/

  initCAN_0();             /* Initialize FlexCAN 0 & one of its buffers for transmit*/

// TransmitMsg();           /* Transmit one message from a FlexCAN 0 buffer */     

//  RecieveMsg();            /* Wait for the message to be recieved at FlexCAN 1 */

  while (1)

  {            

       IdleCtr++;    /* Idle loop: increment counter */  

       TransmitMsg();           /* Transmit one message from a FlexCAN 0 buffer */     

       RecieveMsg();            /* Wait for the message to be recieved at FlexCAN 1 */           

  }

}

这个是在找的例程的基础上有部分我修改了，在网上看到帖子说配SBC，不明白什么意思，请前辈给予指点

CAN模块原理图