Xmega Application Note

flash_write_example.c

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/* This file has been prepared for Doxygen automatic documentation generation.*/
/* Define flash memory and page size of target MCU */
#define APP_END 0x40000
#define FLASH_PAGE_SIZE 512 //Bytes

#include "sp_driver.h"


/* Temporary storage used for NVM-workaround. */
uint8_t sleepCtr;
uint8_t statusStore;
uint8_t pmicStore;
uint8_t globalInt;
uint8_t spmintStore;

/* SPM wakeup interrupt */
ISR(NVM_SPM_vect)
{
        /* Disable the SPM interrupt */
        NVM.INTCTRL = (NVM.INTCTRL & ~NVM_SPMLVL_gm);
        /* Restore sleep settings */
        SLEEP.CTRL = sleepCtr;
        /* Restore PMIC status and control registers */
        PMIC.STATUS = statusStore;
        PMIC.CTRL = pmicStore;
        /* Restore SPM interruptsettings */
        NVM.INTCTRL = spmintStore;
        /* Restore global interrupt settings */
        SREG = globalInt;
        return;
}

/* Set interrupt vector location to boot section of flash */
void PMIC_SetVectorLocationToBoot( void )
{
        uint8_t temp = PMIC.CTRL | PMIC_IVSEL_bm;
        CCP = CCP_IOREG_gc;
        PMIC.CTRL = temp;
}

/*Set interrupt vector location to application section of flash */
void PMIC_SetVectorLocationToApplication( void )
{
        uint8_t temp = PMIC.CTRL & ~PMIC_IVSEL_bm;
        CCP = CCP_IOREG_gc;
        PMIC.CTRL = temp;
}

/* Save register settings before entering sleep mode */
void Prepare_to_Sleep( void )
{
        sleepCtr = SLEEP.CTRL;
        /* Set sleep mode to IDLE */
        SLEEP.CTRL =  0x00; 
        /* Save the PMIC Status and control registers */
        statusStore = PMIC.STATUS;                                                              
        pmicStore = PMIC.CTRL;          
        /* Enable only the highest level of interrupts */                                                                       
        PMIC.CTRL = (PMIC.CTRL & ~PMIC_HILVLEN_bm) | PMIC_HILVLEN_bm;
        /* Save SREG for later use */
        globalInt = SREG;
        /* Enable global interrupts */
        sei();
        /* Save SPM interrupt settings for later */ 
        spmintStore = NVM.INTCTRL;
}

/* New function declarations used for the NVM-workaround */
void EraseApplicationPage(uint32_t address)
{
        /*Set the correct settings and store critical registers before NVM-workaround*/
        Prepare_to_Sleep();
        /*Assembly "function" to preform page erase*/
        SP_EraseApplicationPage(address);
}

void EraseWriteApplicationPage(uint32_t address)
{
        /*Set the correct settings and store critical registers before NVM-workaround*/
        Prepare_to_Sleep(); 
        /*Assembly "function" to preform page erase-write*/
        SP_EraseWriteApplicationPage(address);
}

void ClearFlashBuffer(void)
{
        /*Set the correct settings and store critical registers before NVM-workaround*/
        Prepare_to_Sleep(); 
        /*Assembly "function" to erase flash buffer*/
        SP_EraseFlashBuffer();
}

void LoadFlashWord(uint32_t address, uint16_t word)
{
        /*Set the correct settings and store critical registers before NVM-workaround*/
        Prepare_to_Sleep();   
        /*Assembly "function" to load flash buffer*/
        SP_LoadFlashWord(address, word);
}


int main(void)
{
        /* Assume success until proven otherwise. */
        bool success = true;
        PMIC_SetVectorLocationToBoot();
        /* Fill the entire application section of the flash memory with bogus data */
        for (uint32_t address = 0; address < APP_END; address+=FLASH_PAGE_SIZE) {
        
                /* Load flash buffer with data */
                ClearFlashBuffer(); //Clear the flash buffer first to avoid data corruption
                for (uint16_t i = 0; i < FLASH_PAGE_SIZE; i += 2) {
                        uint8_t lowByte = i;
                        uint8_t highByte = i+1;
                        
                        LoadFlashWord((uint32_t)i, ((uint16_t) highByte << 8) | lowByte);
                        SP_WaitForSPM();
                }
                
                /* Perform erase-page write. */ 
                EraseWriteApplicationPage(address);
        }
        
        /* Check if data is written correctly */
        for (uint32_t address = 0; address < APP_END; address++)
        {
           if(SP_ReadByte(address) != (uint8_t)address) success = false;
        }
        
        /* Allow for breakpoint to check the value of "success". */
        if (success) {
                while(true){
                        nop();
                }
        } else {
                while(true){
                        nop();
                }
        }
}