how to write .hex file on internal Flash ROM of microcontroller? - c

Question

I want to write a ".hex" file of size 28 kb flash on to that Internal flashROM of size 32 kb.The above mentioned question is for initialising the flashROM. What i am doing for writing that file and the code is mentioned below:
I am having a .hex file in Intel hex format, that i have to read and write to internal
FlashROM of At91(8051) microcontroller.
Open the .hex file in "rb+" mode.
Get the length of the file and set the pointer to start address(zeroth address).
As I need to write that file page by page and pagesize in my case is 256 bytes, I have
divide the file by 256.
After that I have try to write that file.
Please let me know where I am going wrong. The code is given below.
int a,b; int size,last_chunk; FILE *file; char *buffer1,name[20]; unsigned long fileLen;
file = fopen("flashROM.hex", "rb+");
if (!file)
{
fprintf(stderr, "Unable to open file %s", name);
return;
}
fseek(file, 0, SEEK_END);
fileLen=ftell(file);
printf("the file length is:%d\n",fileLen);
fseek(file, 0, SEEK_SET);
//Allocate memory
buffer1 =(char *)malloc(fileLen+1);
if (!buffer1)
{
fprintf(stderr, "Memory error!");
fclose(file);
return;
}
//Read file contents into buffer
fread(buffer1, fileLen, 1, file);
/* We have to divide the entire file into chunks of 256 bytes*/
size = fileLen/256;
printf("\nsize = %d\n",size);
last_chunk = fileLen%256;
printf("\nlast chunk = %d bytes\n",last_chunk);
address = 0x0000;
printf("File upgradation should start from :%.4x",address);
for(a=0;a<=size;a++)
{
write(fd,&buffer1,size);
printf("Iteration=[%d]\t Data=[%x]\n",a,*buffer1);
usleep(5000);
}
for(b=0;b<=last_chunk;b++)
{
write(fd,&buffer1,1);
usleep(5000);
}
After executing the binary of above mentioned program, my result is mentioned below:
Writing upgrade file
the file length is:30855
size = 120
last chunk = 135 bytes
File upgradation should start from :0000
Iteration=[0] Data=[3a]
Iteration=[1] Data=[3a]
Iteration=[2] Data=[3a]
Iteration=[3] Data=[3a]
Iteration=[4] Data=[3a]
Iteration=[5] Data=[3a]
Iteration=[6] Data=[3a]
Iteration=[7] Data=[3a]
I don't know, why the data is always "3a", its not clear.
Please let me know where i have done wrong in programming.

Answer 1

You need a special tool that reads the .hex file and does whatever is necessary to write it into the flash memory of your controller (JTAG, talk to a bootloader via whatever means of communication, ...).
The tool depends on your specific microcontroller family. 8051 is not enough information, there is a huge variety of 8051s from many vendors.

Answer 2

Try using "wb+" as your mode for fopen
Opening the file as writable will create it if it doesn't already exist.
The code where you write data also looks suspect. You're passing a pointer to a pointer to a buffer into write rather than a simple pointer to your buffer. I also don't see the pointer getting incremented so you're writing the same data repeatedly.
You could try replacing your writing code with something like the following:
char* ptr = buffer1;
for(a=0;a<=size;a++)
{
write(fd,ptr,size);
ptr+=size;
printf("Iteration=[%d]\t Data=[%x]\n",a,*buffer1);
usleep(5000);
}
for(b=0;b<=last_chunk;b++)
{
write(fd,ptr,1);
usleep(5000);
}