Hard Fault error

[tkjmail2]

Posted on March 13, 2010 at 22:53

Hard Fault error

[domen23]

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?)

[tkjmail2]

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]

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

[tkjmail2]

Posted on May 17, 2011 at 13:43

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

Thanks anyways. Thomas

[Tesla DeLorean]

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

[tkjmail2]

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

[Tesla DeLorean]

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]);

[Tesla DeLorean]

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); }

[tkjmail2]

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