nrf52832 flash erase

[amywei]

HI,All

Before I erase flash ,I must do memcpy().  I do not know why.

As follow,  after i delete the function memcpy( (uint8_t*)&data_buff[0], pdata, len),  when i write data[8]={0x01,02,03,04,05,06,07,08} to flash, I see the memory is 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 by debug.

Can you tell me why i must do memcpy();

I use sdk 12.3 ,  fs to do the flash reading and writing.

Thanks.

void my_fs_update(uint8_t * pdata, uint16_t len)
{
	fs_ret_t ret;
	
	len = len>8?8:len;
	
	memcpy( (uint8_t*)&data_buff[0], pdata, len);
	
	ret = fs_erase(&fs_config, fs_config.p_start_addr, 1, NULL);
	
	if ( FS_SUCCESS != ret )
	{
		printf("fs erase err\r\n");
	}
}

Amy

[Vidar Berg]

Hi,

Both source and destination pointer must be word aligned, have you checked if pdata pointer is word aligned? You can enforce word alignment by using the __ALIGN() keyword when defining the variable.

e.g.,__ALIGN(4) static uin8_t pdata[128] ;

 

 

[amywei]

Thanks

Here is only erase flash.  I think  fs_erase(&fs_config, fs_config.p_start_addr, 1, NULL) is necessary.,but why function memcpy() is also necessary?

[Vidar Berg]

Yes, you need to perform an erase before you can update flash content.

Is data_buff the source pointer you are passing to fs_store()? In that case you have to make sure that data_buff contains the data you want to store, which I assume is what the memcpy is doing here.

[amywei]

Thanks,

data_buff is not the source pointer,  the source pointer is save_mac_buff

Here is the fs_store operation

void fs_evt_handler(fs_evt_t const * const evt, fs_ret_t result)
{
	if ( FS_EVT_STORE == evt->id && FS_SUCCESS == result )
	{
		printf("flash store done\r\n");
	}
	else if ( FS_EVT_ERASE == evt->id && FS_SUCCESS == result )
	{
//		printf("flash erase done\r\n");
		fs_store(&fs_config, fs_config.p_start_addr, save_mac_buff, 2, NULL);
	}
}

[Vidar Berg]

Ok, so you are sure that save_mac_buff and data_buff are two separate buffers?  The memcpy routine copies data from "pdata" to "data_buff", which seems to be required to get the correct data stored. Where does save_mac_buff get updated with pdata?