Posted on September 08, 2014 at 08:36
I want to use block of flash(16KB) as eeprom.
I am using STM32F205RBT6 & keil 4.
What I have to do:
1. Store 5Kb of user data & retrieve it on startup.
2. Flash endurance of 10000 cycles is good for my project & I have fixed 16Kb block for it.
What I have done is :
1. OPtion for target-> target-> (check)IROM1 ; Start 0x8000000 ; size 0x4000 OPtion for target-> target-> (check)IROM2 ; Start 0x8008000 ; size 0x18000
i.e fixing flash block 0x80004000 fix for eeprom whose size is 16Kb
2. Flah write code for 5Kb data:
void flash_write(void)
{
uint32_t address = 0x08004000;
uint32_t data;
uint32_t cnt = 0;
/* read entire sector */
while(address < 0x08008000)
{
data = *(__IO uint32_t*)address;
flah_union.data_u32[cnt++] = data;
address = address + 4;
}
/* fill the array */
for( cnt = 0 ; cnt < 5120 ; cnt++ )
{
flah_union.data_u8[cnt] = g_ft232_arr_data[cnt];
}
/* unlock flash */
FLASH_Unlock();
/* Clear pending flags (if any) */
FLASH_ClearFlag(FLASH_FLAG_EOP | FLASH_FLAG_OPERR | FLASH_FLAG_WRPERR | FLASH_FLAG_PGAERR | FLASH_FLAG_PGPERR|FLASH_FLAG_PGSERR);
/* erase the entire sector */
if (FLASH_EraseSector(FLASH_Sector_1, VoltageRange_3) != FLASH_COMPLETE)
{
/* Error occurred while sector erase.
User can add here some code to deal with this error */
while (1)
{
}
}
/* write back array */
address = 0x08004000;
cnt = 0;
while(address < 0x08008000)
{
if (FLASH_ProgramWord(address, flah_union.data_u32[cnt++]) == FLASH_COMPLETE)
{
address = address + 4;
}
else
{
while (1)
{
}
}
}
FLASH_Lock();
}
3. Flash read code for 5Kb data:
void flash_read(void)
{
uint32_t address = 0x08004000;
uint32_t data;
uint32_t cnt = 0;
/* read entire sector */
while(address < 0x08008000)
{
data = *(__IO uint32_t*)address;
flah_union.data_u32[cnt++] = data;
address = address + 4;
}
/* fill the array */
for( cnt = 0 ; cnt < 5120 ; cnt++ )
{
g_ft232_arr_data[cnt] = flah_union.data_u8[cnt];
}
}
My queries:
1. Do I need to disable interrupts before reading or writing to flash even if I had defines separate block for eeprom, as I said earlier.
2. Since I am writing to flash & also while write to flash, code is getting executing from flash i.e code for reading/writing flash. Do I need to move the code to Ram?
If yes how
Edit: All the flash function inside write/read functions are called from standard peripheral library provided by ST.
