AVR Freaks

Guys, I have a function that returns a bit from the exFAT heap to mark a new cluster.  But for some reason there are errors when I create thousands of folders and files to test the system.

When I test the routine to start returning bits using the following, it works:

Basically, the function returns the first free bit it finds.

//	test to see if the problem is in this routine!!!!!!!!
	static unsigned int test = 8;
	clear_cluster(stream, test);

	//return address of bit allocated
	return test++;

This is the function:

unsigned int dir_get_cluster_bit(FILEX * stream){

	// base the pointer
	unsigned char * bitMap = stream->cache;

	/* Bit Map table, its a bit like the FAT table in FAT32 only it is in bits*/
	unsigned int fat_table = data_to_cpu32(stream->exFAT_Boot_Sector->ClusterHeapOffset) + stream->partition_index;

	// read first sector
	dma_hardware_read(1, fat_table, 1, stream->cache, 0);

	unsigned int byte = 0, sector = 0;

	// scan sector for a free bit, i.e. one or more bits are Zero
	while(* bitMap == 0xff){

		byte++, bitMap++;

		// stop arithmetic errors when byte is zero
		if(((byte % 512) == 0) && (byte != 0)){

			// move to next sector
			sector++;
			byte = 0;

			// reset bitmap to start of sector
			bitMap = (unsigned char *)&bitMap[0];

			// read next sector
			dma_hardware_read(1, fat_table + sector, 1, stream->cache, 0);
		}
	}

	// UnMap free bit location
	unsigned int bit = free_bit[* bitMap];

	// write bit to target byte and update
	* bitMap |= (unsigned char)1 << bit;

	// write first FAT bit entry
	dma_hardware_write(1, fat_table + sector, 1, stream->cache, 0);

	unsigned int new_cluster = ((sector * 512) + (byte * 8) + bit + 2);

	clear_cluster(stream, new_cluster);

//	test to see if the problem is in this routine!!!!!!!!
//	static unsigned int test = 8;
//	clear_cluster(stream, test);

	//return address of bit allocated
	return new_cluster;
}

So, when I find a free cluster bit, i.e. a zero int the byte, I mark it and return the address that the bit was found.