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标题: mscan不能发送can报文 [打印本页]

作者: flexraybeginer 时间: 2010-12-13 19:54 标题: mscan不能发送can报文

本帖最后由 flexraybeginer 于 2010-12-13 19:56 编辑

芯片用的是mc9s12xf512，每隔400毫秒发送次can报文，但总线电平无反应（用canoe和示波器测试），用仿真器观测，程序停止在can发送程序while（(CAN0TFLG & u8TxBuffer) != u8TxBuffer)
具体程序如下：
#include "mc9s12xf512.h"

UINT8 u8TxBuffer[] = "S12XF512";

void DelayMS(unsigned int time) //100ms
{
PITCFLMT = 0x00; //关闭计时器
PITCE = 0x01; //使能通道1
PITMUX = 0x00;  //使用宏时钟0
PITMTLD0 = 0xFF; //宏时钟为7us
PITLD0 = time*15625-1;  //timeus
PITTF = 0x01; // 清时钟标志位
PITCFLMT = 0x80; //使能计时器
while(!(PITTF&0x01));
PITTF = 0x01;
PITCFLMT = 0x00;
}

void vfnClock_Settings(void)
{
/* Bus Clock = OSCCLK * (SYNR+1) / ((REFDV+1)(2*POSTDIV)) */
/*    40MHz =  4MHz  * (9+1) / (1)                         */
PLLCTL_PLLON = 0;    /* Disable the PLL */
SYNR_SYNDIV = 0x09;       /* Set PLL synthesizer register to 9 */
REFDV_REFDIV = 0x00;    /* Set PLL divider register to 0 */

/* Fvco = 2*OSCCLK*(SYNR+1)/(REFDV+1) = 8MHz* 10/1 = 80MHz */
/*                                  -> VCOFRQ = 01b       */
SYNR_VCOFRQ1 = 0;
SYNR_VCOFRQ0 = 1;

/* Fref = OSCCLK/(REFDV+1) = 4MHz/1 = 4MHz -> REFRQ= 01b    */
REFDV_REFFRQ1 = 0;
REFDV_REFFRQ0 = 1;

PLLCTL_PLLON = 1; /* PLL enabled */

      while(!CRGFLG_LOCK)
         ;    /* Wait until the PLL is within the desired frequency */

CLKSEL_PLLSEL = 1; /* Select clock source from PLL */
}

void main(void) {
  /* put your own code here */
UINT8 p,k=0;
   p = 1;

vfnClock_Settings();
vfnCAN_Init();

EnableInterrupts;
  for(;;) {

p = u8CAN_SendFrame(0xD8E00000,0x00,8 , u8TxBuffer);
DelayMS(4);//400毫秒
k = k ^ 1;
if(p == 0) p = 1;
_FEED_COP(); /* feeds the dog */
  } /* loop forever */
  /* please make sure that you never leave main */
}

下面是can发送驱动函数
#include "CAN_driver.h"
/*******************************************************************************/
/**
* \brief MSCAN configuration, baud rate = 500kbps, 16 bit acceptance filters
* \author Jaime Orozco
* \param void
* \return void
*/
void vfnCAN_Init(void)
{
CAN0CTL0 = 0x01; /* MSCAN in initialization mode */
      while (!(CAN0CTL1_INITAK))
         ;       /* Wait for initialization mode acknowledge */

CAN0CTL1_CANE = 1;    /* Enable MSCAN module */
CAN0CTL1_CLKSRC = 0; /* Clock source is OSCCLK, CANCLK = 4MHz */
CAN0CTL1_LOOPB = 0;    /* Set to 1 for LoopBack Mode, 0 otherwise */
CAN0CTL1_LISTEN = 0; /* Not listen only mode */

/* Baud rate = CANCLK/(Prescaler * time quantas) */
CAN0BTR1_TSEG_10 = 0x04; /* Time Segment 1 = 5 */
CAN0BTR1_TSEG_20 = 0x01; /* Time Segment 2 = 2 */
                              /* TSEG1 + TSEG2 + SYNCH_SEG = 8 time quantas */

/* Prescaler = CANCLK/(Baud rate * time quantas) = 4MHz/(500kHz * 8) = 1 */
CAN0BTR0_BRP = 0x00; /* Baud rate prescaler = 1 */
CAN0BTR0_SJW = 0x01; /* Sinchronization jump width = 2 clock cycles */

CAN0BTR1_SAMP = 0;    /* One sample per bit */


CAN0IDAC_IDAM = 0x01;             /* Four 16-bit acceptance filters */

CAN0IDAR0 = ACC_CODE_ID100_HIGH; /* 16 bit Filter 0 */
CAN0IDMR0 = MASK_CODE_ST_ID_HIGH;
CAN0IDAR1 = ACC_CODE_ID100_LOW;
CAN0IDMR1 = MASK_CODE_ST_ID_LOW;

CAN0IDAR2 = 0x00;                /* 16 bit Filter 1 */
CAN0IDMR2 = MASK_CODE_ST_ID_HIGH;
CAN0IDAR3 = 0x00;
CAN0IDMR3 = MASK_CODE_ST_ID_LOW;

CAN0IDAR4 = 0x00;                /* 16 bit Filter 2 */
CAN0IDMR4 = MASK_CODE_ST_ID_HIGH;
CAN0IDAR5 = 0x00;
CAN0IDMR5 = MASK_CODE_ST_ID_LOW;

CAN0IDAR6 = 0x00;                /* 16 bit Filter 3 */
CAN0IDMR6 = MASK_CODE_ST_ID_HIGH;
CAN0IDAR7 = 0x00;
CAN0IDMR7 = MASK_CODE_ST_ID_LOW;

CAN0CTL0 = 0x00;          /* Exit initialization mode request */
      while (CAN0CTL1_INITAK)
         ;             /* Wait for normal mode */

      while(!(CAN0CTL0_SYNCH))
         ;                /* Wait for CAN synchronization */

CAN0RFLG_RXF = 1;    /* Clear receiver flags */
CAN0RIER_RXFIE = 1;    /* Enable Full Receive Buffer interrupt */

}
/*******************************************************************************/
/**
* \brief CAN frame transmission
* \author Jaime Orozco
* \param u32ID: Identifier, u8Prio: Priority, \n
         u8Length: Frame size, u8TxData: Data array
* \return void
*/
UINT8 u8CAN_SendFrame(UINT32 u32ID, UINT8 u8Prio, UINT8 u8Length, UINT8 *u8TxData)
{
/* Transmission buffer */
UINT8 u8TxBuffer = {0};

/* Index to data within the transmission buffer */
UINT8 u8Index;

if (!CAN0TFLG)             /* Retrun if Transmit Buffer is full */
      return ERR_BUFFER_FULL;
CAN0TBSEL = CAN0TFLG;    /* Select lowest empty buffer */
u8TxBuffer = CAN0TBSEL;  /* Backup selected buffer */

*((UINT32 *) ((UINT32)(&CAN0TXIDR0)))= u32ID; /* Load Id to IDR Registers */

      /* Load data to Data Segment Registers */
      for (u8Index=0;u8Index<u8Length;u8Index++) {
         *(&CAN0TXDSR0 + u8Index) = u8TxData[u8Index];
      }
CAN0TXDLR = u8Length; /* Set Data Length Code */
CAN0TXTBPR = u8Prio; /* Set Priority */
CAN0TFLG = u8TxBuffer;  /* Start transmission */

      while ( (CAN0TFLG & u8TxBuffer) != u8TxBuffer)
         ;  /* Wait for Transmission completion */

return NO_ERR;
}

作者: flexraybeginer 时间: 2010-12-14 11:59

每次怎么都是自问自答的我。
因为用的can收发芯片是MC33742，还需要一些初始化工作

作者: dfmc 时间: 2011-2-20 20:51

我也遇到过这种情况，发送没有完成，while语句通不过，不知道怎么回事。但是去掉while后，总线是发出来了。

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