How to write data of arbitrary type to FLASH of XMC4400?

Hi all,

I am trying to save a single instance of a typedeffed data type to the flash of the XMC4400 for later use (only an example here, in reality it is a larger configuration struct, but not larger than the page size of 256 bytes). As a target, I chose the first page of the user configurable block 0 (UCB0) of the flash of XMC4400, starting address is 0xc000000.

Here is a portion of sample code that I tried - loading the data is not a problem as the flash can be accessed as RAM, but saving the data does not work - though I'm using the latest version of the XMClib -> <xmc_flash.h> and <xmc4_flash.h>. The codes executes without exceptions, the flash status indicates programming mode after save_data(..), but if I look at 0xc000000 with the debugger I notice nothing has happened. Consequently, after load_data() the variable reads random data.

Can anyone help? Provide some code that will succeed to write this variable to the flash?

Thanks,
Niklas

Code:

#include <DAVE.h>

#include <XMC4400.h>

#include <core_cm4.h>

#include <xmc_flash.h>



#define FLASH_ADDRESS XMC_FLASH_UCB0



typedef struct my_type {

        bool foo;

        void (*foo_handler)(void);

        float bar;

        //etc...

}TYPE_t;



TYPE_t data;



void save_data(uint32_t* address)

{

        uint32_t page[XMC_FLASH_WORDS_PER_PAGE];

        TYPE_t* data_ptr = &data;



        //initialize a buffer of the size of one flash page

        for (uint32_t i=0; i<XMC_FLASH_WORDS_PER_PAGE; ++i)

                page[i]=0;



        //copy the target data word by word into the buffer

        for (uint32_t i=0; i<sizeof(TYPE_t)/4; ++i)

                page[i]= *(uint32_t*)data_ptr++;



        

        XMC_FLASH_ClearStatus();

        

        //attempt to write the buffer (=one page) to the flash -> executes but does not do anything???

        XMC_FLASH_ProgramPage(FLASH_ADDRESS, page);

}



void load_data(void)

{

        data = *((TYPE_t*)FLASH_ADDRESS);

}



int main(void)

{

        SystemInit();

        

        data.foo = true;

        data.foo_handler = NULL;

        data.bar = 100e-9;



        save_data(FLASH_ADDRESS);

        

        data.foo = false;

        data.bar = 0;



        load_data();



        while(1U);

}