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tkjmail2
tkjmail2
Associate III
March 13, 2010
Question

Hard Fault error

  • March 13, 2010
  • 15 replies
  • 2324 views
Posted on March 13, 2010 at 22:53

Hard Fault error

    This topic has been closed for replies.

    15 replies

    domen23
    domen23
    Associate II
    May 17, 2011
    Posted on May 17, 2011 at 13:43

    One of following two accesses is definitely not going to be aligned to short boundary, and ARM doesn't handle this. (Also, they look wrong even if it'd worked?)

    Tesla DeLorean
    Tesla DeLorean
    Guru
    May 17, 2011
    Posted on May 17, 2011 at 13:43

    The following methods should be safe, they operate one byte at a time.

    unsigned short a;

    unsigned char b[100];

    memcpy(&a,&b[x+ 0],sizeof(unsigned short));

    -OR-

    a = ((unsigned short)b[x + 0] << 0) + ((unsigned short)b[x + 1] << 8);

    You just can't use casts to arbitrarily change a pointer type and load it.

    -Clive

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    tkjmail2
    tkjmail2Author
    Associate III
    May 17, 2011
    Posted on May 17, 2011 at 13:43

    Oh...?

    But then how would you connect two chars (bytes) to a 16-bit usigned integer (u16)?

    Thomas

    Tesla DeLorean
    Tesla DeLorean
    Guru
    May 17, 2011
    Posted on May 17, 2011 at 13:43

    It was an either/or suggestion.

    memcpy() works well for structures, and is often optimized to an intrinsic.

    -Clive
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    tkjmail2
    tkjmail2Author
    Associate III
    May 17, 2011
    Posted on May 17, 2011 at 13:43

    Why do you use memcpy? Wouldn't the ''a ='' be enough?

    Thanks anyways.

    Thomas

    Tesla DeLorean
    Tesla DeLorean
    Guru
    May 17, 2011
    Posted on May 17, 2011 at 13:43

    There seems to be a misunderstanding of how to use pointers, you don't need the '&' when you access the content of str[], only when you want the address (ie &str[])

    color = ((unsigned short)(str[ 2 * temp]) << 0) + ((unsigned short)(str[ (2 * temp)+1]) << 8);

    How are you calling the routine?

    void foo(const unsigned char *str);

    const unsigned char data[] = { 0x01, 0x02, 0x03, 0x04 };

    foo(data); // Or foo(&data[0]);

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    tkjmail2
    tkjmail2Author
    Associate III
    May 17, 2011
    Posted on May 17, 2011 at 13:43

    I can't make it work... Remember, I'm using pointers!

    If I try this code, it doesn't get the correct value:

    u16 color;

    color = ((unsigned short)(&str[ 2 * temp]) << 0) + ((unsigned short)(&str[ 2 * temp+1]) << 8);

    And if I use this code, it goes into the Hard Fault routine again:

    u16 color;

    memcpy(&color,&str[2 * temp],sizeof(unsigned short)); 

    Best Regards

    Thomas Jespersen

    tkjmail2
    tkjmail2Author
    Associate III
    May 17, 2011
    Posted on May 17, 2011 at 13:43

    After it has shown a couple of lines (I think it's 5 pixel lines) of the image, it goes into the Hard Fault routine.

    OBS: The image is 56x56 pixels!

    Thomas

    Tesla DeLorean
    Tesla DeLorean
    Guru
    May 17, 2011
    Posted on May 17, 2011 at 13:43

    void DispPic(u16 x0, u16 y0, const unsigned char *str)

    {

      typedef union

      {

        u16 U16;

        u8 U8[2];

      } ColorTypeDef;

     u32 temp;

     u16 i, j;

     u16 imageWidth;

     u16 imageHeight;

     ColorTypeDef color;

     color.U8[1] = str[0];

     color.U8[0] = str[1];

     imageWidth = color.U16;

     color.U8[1] = str[2];

     color.U8[0] = str[3];

     imageHeight = color.U16;

     temp = 4;

     for(j=0; j<imageHeight; j++)

     {

        Lcd_SetCursor(x0, y0);

        LCD_WriteRAM_Prepare();

        for(i=0; i<imageWidth; i++)

        { //Write all pixels to ram, and then update display (fast)

          color.U8[1] = str[temp++];

          color.U8[0] = str[temp++];

          LCD_WriteRAM(color.U16);

        }

        y0++;

      }

    }

    const unsigned char data[] = {

      0x00, 0x03, // 3 Wide

      0x00, 0x02, // 2 High

      0xAA, 0xAA,  0xBB, 0xBB,  0xCC, 0xCC,

      0xDD, 0xDD,  0xEE, 0xEE,  0xFF, 0xFF };

    int main(int argc, char **argv)

    {

      DispPic(10, 12, data);

      return(1);

    }

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    Tesla DeLorean
    Tesla DeLorean
    Guru
    May 17, 2011
    Posted on May 17, 2011 at 13:43

    The Hard Fault indicates you are reading/writing to an illegal location.

    You'll have to debug it. Suggest removing the LCD_xxx calls and see if it still traps. Try outputting some instrumentation to the serial debug port, etc.

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