Regards,
Kiran

I figured out what my problem is. My program is running from flash.

Have you tried writing multiple pages at a time? My single page write in my project works. But for multiple writes… I put a loop to call my write function multiple time. It always gives me a prefetch abort if I run the program. However if I step over the function each time, it writes the pages successfully. I am using IAR btw.

I tried to put a loop on your code as well. Same thing happens. Umm, am I using the right approach? any idea?

Thank you.

Evon

.text 0×00202000 0x631c

This shows the start address and size of a segment, in this example the “.text” (code) segment which has a size of 0x631c (25372) bytes.

If you are writing in C, there is also RAM used by the stack and the heap which cannot be easily calculated at compile time.

The powcon and pllcon registers are both 0. To get the desired result what changes do I need to make?

int main()
{
GP0CON = 0×00; // for p4.2
while(1){ //infinite loop
T0LD = 0xA000; // Counter Value
T0CON = 0xC0 // count down,system core clock divided by 1
// periodic mode

while(T0VAL!=0){} //producing delay

T0CON=0;

GP4DAT ^= 0×04000000; //complementing pin4.2
}
}
But on oscilloscope when I check the pin4.2 the result is not 1msec.
but a greater value, I have checked powcon and pllcon registers,their values are both 0.
Please Advise.

Code memory is where the program is stored – this would be assigned to ROM (actually flash memory in the ARM).
Data memory is where the program stores its data – this would be assigned to RAM.
You might also see an allocation for stack space which is in RAM too.

You can compare the numbers in the map file with the memory map of your particular chip to see if your program is going to fit in the available memory.

for(i = 0; i < size; i++)
{
buf = (*(data+4*i)) | (*(data+4*i+1) << 8 ) | (*(data+4*i+2) << 16) | (*(data+4*i+3) << 24);
*(dest+i) = buf;
}

thanks for this great example.
The problems, that some users might have, seems to be related to the type conversion that’s going on. When you try to read the char buffer (char buf[96];) with 4-Byte alignment then this only works if the address of buf is (coincidentally or otherwise) 4-byte aligned! Otherwise the uC will throw a data abort exception. The code works perfectly if the 32bit word is assembled from the char array without the pointer casting, like so:
——————————————
RUNFROMRAM int FlashWrite(unsigned int address, char *data, unsigned int size)
{
unsigned int i;
unsigned int page;
unsigned int buf;
unsigned int *dest = (unsigned int *) address;

size = (size + 3) / 4;

for(i = 0; i < size; i++)
{
buf = (*(data+4*i)) | (*(data+4*i+1) << 8) | (*(data+4*i+2) << 16) | (*(data+4*i+3) <MC_FCR = AT91C_MC_WRITE_KEY | AT91C_MC_FCMD_START_PROG | (page << 8); // Write the page to Flash memory.

—————————————————
Hope this helps those users who found themselves stuck in exceptions!

Regards
Stefan

Is there any chance you could post some sample gcc code somewhere?

My code is hanging too, but I’m unable to fix it. Everthing seems
to be set right; write cycle timer, executing from ram, using the
example code, but it hangs just as FCR is written :/

Paul.

The code does not execute beyond the point mentioned (if I set a break point). If I break the code with the debugger after it stopped it PC is 0x0000C (some exeption). To make things more interesting the code does not crash if I step it with the debugger. Also note, irrespective if the program crash or not, the flash is always written successfully. (I have checked all the things you mentioned and they look OK)