SOS--K10P100M72SF1RM--flexcan配置问题

avva123456

如下代码：这个波特率是采用k60的配置的，在测试过程中，只有83k和125k可以测通，其它波特率测不通，示波器看波形83k的是86k，125k的是130k；新手不知道怎么算的，sos大神，sos大牛。。。
补充说明：k60的开发板和我自己弄的板子都是使用50M的晶振，但是看例程里面k60是按48M来算can波特率的那些参数，而自己的k10却按48M算波特率却有误差，按50M就是正常的波特率，并且k10的500k和1m的波特率有误差。
    switch (baudrateKHz)
    {
          case (33): // 33.33K
             if(CAN_CTRL1_REG(CANBaseAdd) & CAN_CTRL1_CLKSRC_MASK)
             {
  // 48M/120= 400k sclock, 12Tq
  // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
  // RJW = 3, PSEG1 = 4, PSEG2 = 4,PRESDIV = 120
  CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
            | CAN_CTRL1_RJW(2)
            | CAN_CTRL1_PSEG1(3)
            | CAN_CTRL1_PSEG2(3)
            | CAN_CTRL1_PRESDIV(119));
             }
             else
             {
  // 12M/20= 600k sclock, 18Tq
  // PROPSEG = 1, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
  // RJW = 4, PSEG1 = 8, PSEG2 = 8,PRESDIV = 20
  CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(0)
            | CAN_CTRL1_PROPSEG(3)
                                               | CAN_CTRL1_PSEG1(7)
                                               | CAN_CTRL1_PSEG2(7)
                                               | CAN_CTRL1_PRESDIV(19));
             }
             break;
            
          case (83): // 83.33K
             if(CAN_CTRL1_REG(CANBaseAdd) & CAN_CTRL1_CLKSRC_MASK)
             {
  // 48M/48= 1M sclock, 12Tq
  // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
  // RJW = 3, PSEG1 = 4, PSEG2 = 4,PRESDIV = 48
  CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
      | CAN_CTRL1_RJW(2)
      | CAN_CTRL1_PSEG1(3)
      | CAN_CTRL1_PSEG2(3)
      | CAN_CTRL1_PRESDIV(47));
             }
             else
             {
     // 12M/12= 1M sclock, 12Tq
     // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
     // RJW = 3, PSEG1 = 4, PSEG2 = 4,PRESDIV = 12
     CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
            | CAN_CTRL1_RJW(2)
            | CAN_CTRL1_PSEG1(3)
            | CAN_CTRL1_PSEG2(3)
            | CAN_CTRL1_PRESDIV(11));
             }
             break;
          case (50):
             if(CAN_CTRL1_REG(CANBaseAdd) & CAN_CTRL1_CLKSRC_MASK)
             {               
     // 48M/80= 0.6M sclock, 12Tq
     // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
     // RJW = 3, PSEG1 = 4, PSEG2 = 4, PRESDIV = 40
     CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
            | CAN_CTRL1_RJW(1)
            | CAN_CTRL1_PSEG1(3)
            | CAN_CTRL1_PSEG2(3)
            | CAN_CTRL1_PRESDIV(79));
             }
             else
             {
     // 12M/20= 0.6M sclock, 12Tq
     // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
     // RJW = 3, PSEG1 = 4, PSEG2 = 4, PRESDIV = 20                
     CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
            | CAN_CTRL1_RJW(2)
            | CAN_CTRL1_PSEG1(3)
            | CAN_CTRL1_PSEG2(3)
            | CAN_CTRL1_PRESDIV(19));                  
             }
             break;
          case (100):
             if(CAN_CTRL1_REG(CANBaseAdd) & CAN_CTRL1_CLKSRC_MASK)
             {
     // 48M/40= 1.2M sclock, 12Tq
     // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
     // RJW = 3, PSEG1 = 4, PSEG2 = 4, PRESDIV = 40
     CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
            | CAN_CTRL1_RJW(2)
            | CAN_CTRL1_PSEG1(3)
            | CAN_CTRL1_PSEG2(3)
            | CAN_CTRL1_PRESDIV(39));
             }
             else
             {
     // 12M/10= 1.2M sclock, 12Tq
     // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
     // RJW = 3, PSEG1 = 4, PSEG2 = 4, PRESDIV = 10
     CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
            | CAN_CTRL1_RJW(2)
            | CAN_CTRL1_PSEG1(3)
            | CAN_CTRL1_PSEG2(3)
            | CAN_CTRL1_PRESDIV(9));                  
             }
             break;
          case (125):
             if(CAN_CTRL1_REG(CANBaseAdd) & CAN_CTRL1_CLKSRC_MASK)
             {                
     // 48M/32= 1.5M sclock, 12Tq
     // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
     // RJW = 3, PSEG1 = 4, PSEG2 = 4, PRESDIV = 32
     CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
               | CAN_CTRL1_RJW(2)
               | CAN_CTRL1_PSEG1(3)
               | CAN_CTRL1_PSEG2(3)
               | CAN_CTRL1_PRESDIV(31));
             }
             else
             {
     // 12M/8= 1.5M sclock, 12Tq
     // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
     // RJW = 3, PSEG1 = 4, PSEG2 = 4, PRESDIV = 8
     CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
            | CAN_CTRL1_RJW(2)
            | CAN_CTRL1_PSEG1(3)
            | CAN_CTRL1_PSEG2(3)
            | CAN_CTRL1_PRESDIV(7));                 
             }
             break;
          case (250):
             if(CAN_CTRL1_REG(CANBaseAdd) & CAN_CTRL1_CLKSRC_MASK)
             {               
     // 48M/16= 3M sclock, 12Tq
     // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
     // RJW = 2, PSEG1 = 4, PSEG2 = 4, PRESDIV = 16
     CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
            | CAN_CTRL1_RJW(1)
            | CAN_CTRL1_PSEG1(3)
            | CAN_CTRL1_PSEG2(3)
            | CAN_CTRL1_PRESDIV(15));
             }
             else
             {
     // 12M/4= 3M sclock, 12Tq
     // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
     // RJW = 2, PSEG1 = 4, PSEG2 = 4, PRESDIV = 4
     CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
            | CAN_CTRL1_RJW(1)
            | CAN_CTRL1_PSEG1(3)
            | CAN_CTRL1_PSEG2(3)
            | CAN_CTRL1_PRESDIV(3));                  
             }
             break;
          case (500):
             if(CAN_CTRL1_REG(CANBaseAdd) & CAN_CTRL1_CLKSRC_MASK)
             {               
     // 48M/8=6M sclock, 12Tq
     // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
     // RJW = 2, PSEG1 = 4, PSEG2 = 4, PRESDIV = 6
     CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
            | CAN_CTRL1_RJW(1)
            | CAN_CTRL1_PSEG1(3)
            | CAN_CTRL1_PSEG2(3)
            | CAN_CTRL1_PRESDIV(7));
             }
             else
             {
     // 12M/2=6M sclock, 12Tq
     // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
     // RJW = 2, PSEG1 = 4, PSEG2 = 4, PRESDIV = 2
     CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
            | CAN_CTRL1_RJW(1)
            | CAN_CTRL1_PSEG1(3)
            | CAN_CTRL1_PSEG2(3)
            | CAN_CTRL1_PRESDIV(1));                  
             }
             break;
          case (1000):
             if(CAN_CTRL1_REG(CANBaseAdd) & CAN_CTRL1_CLKSRC_MASK)
             {                 
     // 48M/6=8M sclock
     // PROPSEG = 4, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
     // RJW = 1, PSEG1 = 1, PSEG2 = 2, PRESCALER = 6
     CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(3)
            | CAN_CTRL1_RJW(0)
            | CAN_CTRL1_PSEG1(0)
            | CAN_CTRL1_PSEG2(1)
            | CAN_CTRL1_PRESDIV(5));
             }
             else
             { 
     // 12M/1=12M sclock,12Tq
     // PROPSEG = 3, LOM = 0x0, LBUF = 0x0, TSYNC = 0x0, SAMP = 1
     // RJW = 4, PSEG1 = 4, PSEG2 = 4, PRESCALER = 1
     CAN_CTRL1_REG(CANBaseAdd) = (0 | CAN_CTRL1_PROPSEG(2)
            | CAN_CTRL1_RJW(3)
            | CAN_CTRL1_PSEG1(3)
            | CAN_CTRL1_PSEG2(3)
            | CAN_CTRL1_PRESDIV(0));
             }
             break;
          default:
             return 1;
       }

我知道答案 目前已有4人回答

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FSL_TICS_ZJJ

楼主，你好！
我首先来回答你为什么K60按48M测试无误差，但是你按照48M测试确有误差。
因为K60的代码在系统配置的时候就将主频配置为96M，外设时钟配置为48M，而CAN的时钟来源选择为bus clock，所以这里的配置是正确的。
但是你按48M算，你是否将外设频率配置到了48M呢？你的主频应该是100M，而外设频率是50Mhz。
至于具体的波特率是否测的通，我这边需要验证一下。
等我验证完，会给您回复！

avva123456

没错，我这里后来测试了，是按照100m来的，但是重新按100m计算后，k10的33、50、83、125、250的用示波器看，波特率都没啥误差，但是后面的500和1000的就不行了。

avva123456

测试96M和100M发现，96M的各个波特率都能正常，100M（换了PRESDIV值）的500和1000的不行，其它波特率下可以，一直对飞思卡尔的can的波特率参数计算不是很明白（模模糊糊）；不知道能不能详细说下怎么计算得来的参数；比如下面这些数据是怎么计算来的：
CAN_CTRL1_PROPSEG(2)
CAN_CTRL1_RJW(1)
CAN_CTRL1_PSEG1(3)
CAN_CTRL1_PSEG2(3)
CAN_CTRL1_PRESDIV(7))
还有sclock这个数值的计算。好让我等新手知其所以然。

FSL_TICS_ZJJ

我找找相关资料，稍等！

FSL_TICS_ZJJ

回复第 4 楼 于2014-03-03 14:51:34发表:
测试96M和100M发现，96M的各个波特率都能正常，100M（换了PRESDIV值）的500和1000的不行，其它波特率下可以，一直对飞思卡尔的can的波特率参数计算不是很明白（模模糊糊）；不知道能不能详细说下怎么计算得来的参数；比如下面这些数据是怎么计算来的：
CAN_CTRL1_PROPSEG(2)
CAN_CTRL1_RJW(1)
CAN_CTRL1_PSEG1(3)
CAN_CTRL1_PSEG2(3)
CAN_CTRL1_PRESDIV(7))
还有sclock这个数值的计算。好让我等新手知其所以然。
 

不好意思，回复迟了。
楼主请看我们这个应用笔记，讲的比较清楚：
AN1798.pdf (507.19 KB, 下载次数: 42)

2014-3-4 16:51 上传

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