How to used internal EEPROM(read and write operation) of STM32L011F3?

[kalpeshpatil102]

Posted on January 16, 2017 at 17:09

Hi, i am using STM32L011F3 . I am using cube mx and keil mdk 5 ide for programming. In my project I want to write and read  data on internal  EEPROM of stm32L0 11F3.  

I didn't get any library or example tutorial for this . I am new in stm32L011F3 .

please help me.  

thank you 

[Imen.D]

Posted on January 16, 2017 at 18:18

Hello

Patil.Kalpesh,

I recommend you to have a look to the "Flash program memory and data EEPROM (FLASH)" section in your related STM32L0 product reference manual

http://www.st.com/content/ccc/resource/technical/document/reference_manual/21/bd/0f/bd/1c/88/40/f0/DM00108282.pdf/files/DM00108282.pdf/jcr:content/translations/en.DM00108282.pdf

and get idea about read-write from EEPROM.

You can have a look to this example under

http://www.st.com/content/st_com/en/products/embedded-software/mcus-embedded-software/stm32-embedded-software/stm32cube-embedded-software/stm32cubel0.html

which describes how to configure and use the Flash to enable and disable the write protection of the internal FLASH memory:

STM32Cube_FW_L0_V1.7.0\Projects\STM32L031K6-Nucleo\Examples\FLASH\FLASH_WriteProtection

You can inspire from this example to achieve your goal and modify it or add your own code.

Also, you can found a full set of running examples with a EEPROM under ST web page within other STM32CubeXX firmware package (like STM32CubeL4), which can help you as an implementation example to build your application on L0. 

Regards

Imen

[Tesla DeLorean]

Posted on January 16, 2017 at 18:58

Isn't the EEPROM just mapped into regular address space, can't you read it using pointers, or memcpy() ?

[kalpeshpatil102]

Posted on January 17, 2017 at 10:05

thank you @ DAHMEN.IMEN, Turvey.Clive.002 for reply.

I go through STM32L0 product reference manual

http://www.st.com/content/ccc/resource/technical/document/reference_manual/21/bd/0f/bd/1c/88/40/f0/DM00108282.pdf/files/DM00108282.pdf/jcr:content/translations/en.DM00108282.pdf.

on page no. 822 found write function like this '

Write to data EEPROM code example

/*/*/*
 
*(uint8_t *)(DATA_E2_ADDR+i) = DATA_BYTE;
 
*(uint16_t *)(DATA_E2_ADDR+j) = DATA_16B_WORD;
 
*(uint32_t *)(DATA_E2_ADDR) = DATA_32B_WORD;
 
DATA_E2_ADDR is an aligned address in the data EEPROM area. i can be any integer. j must be an even integer. */*/
 
in this function i wrote like this 
 
/*/*/* write function of eeprom write/*/*/*/*/*/*/**
 
unsigned long int DATA_E2_ADDR=8080100;// EEPROM address of stm32L0
 
 
 
int i=0,j=0, DATA_BYTE=3;//
 
*(uint8_t *)(DATA_E2_ADDR+i) = DATA_BYTE;
 
*/*/*/*/*

but didn't get it working or not . and how to perform read operation ?

let me know where i am wrong ?

please some one give example on internal eeprom read and write function that will helpfully for me. 

sorry for poor English 

please help me .

thank you

[Tesla DeLorean]

Posted on January 18, 2017 at 16:57

One has to be careful with the Cortex-M0 as it doesn't not support unaligned memory operations, it will Hard Fault. ie reading a 32-bit value from an odd address

I'm not using the L0, my expectation is the FLASH writing examples will be a good place to start.

For reading I'd suggest using structures, either with pointers to them, or copying the content to a RAM holding buffer using memcpy()

You are familiar with typedef, struct and memcpy(), right?

[kalpeshpatil102]

Posted on January 18, 2017 at 15:58

Hello , thank you to all. please any one can give  simple example  to write and read data on internal EEPROM of stm32L0.  please help me .

thank you 

[Alan Doncaster]

Posted on January 19, 2017 at 13:27

Hi Patil

This works for the STM32l051 on Eclipse, just migrating to Keil so haven't tried it on that yet:

#define DATA_EEPROM_BASE_ADDR ((uint32_t)0x08080000) /* Data EEPROM base address */

#define DATA_EEPROM_END_ADDR ((uint32_t)0x080807FF) /* Data EEPROM end address */

Simple write sequence:

void Write_Registers_to_Eeprom(void)

{

uint32_t i;

uint32_t* p_tFlashRegs;

   i = 0;

   p_tFlashRegs = (uint32_t*)&data_to_write;   /* Point to data to write */

   UnlockEeprom(); /* Unlock the EEPROM and enable flash interrupts */

   FLASH->PECR = FLASH->PECR & ~(FLASH_PECR_ERASE | FLASH_PECR_DATA); /* Reset the ERASE and DATA                                                                               bits in the FLASH_PECR register to disable any residual erase */

   /* Put the next line in a loop if sequential bits to be written with i as loop counter */

   EepromProgram(DATA_EEPROM_BASE_ADDR + (4 * i), *(p_tFlashRegs + i)); /* Increase eeprom address by 4 for each                                                                word to write.  */

   LockEeprom(); /* Lock the EEPROM */

}

Called routines:

/* Unlock the EEPROM: */

void UnlockEeprom(void)

{

   while ((FLASH->SR & FLASH_SR_BSY) != 0) /* Wait for FLASH to be free */

   {

/*   insert timeout test */

   }

   if ((FLASH->PECR & FLASH_PECR_PELOCK) != 0) /* If PELOCK is locked */

   {

      FLASH->PEKEYR = FLASH_PEKEY1; /* Unlock PELOCK */

      FLASH->PEKEYR = FLASH_PEKEY2;

   }

   FLASH->PECR = FLASH->PECR | (FLASH_PECR_ERRIE | FLASH_PECR_EOPIE); /* enable flash interrupts */

}

/**

* Brief This function programs a word of data EEPROM.

* The ERASE bit and DATA bit are cleared in PECR at the beginning

* words are automatically erased if required before programming

* Param addr is the 32-bit EEPROM address to program, data is the 32 bit word to program

* Retval None

*/

void EepromProgram(uint32_t addr, uint32_t ee_data)

{

/* NOTE: The EEPROM must be unlocked and the flash interrupts must have been enabled prior to calling this function.*/

   *(uint32_t *)(addr) = ee_data; /* write data to EEPROM */

   __WFI();

   if (*(uint32_t *)(addr) != ee_data)

   {

      error |= ERROR_PROG_32B_WORD;

   }

}

/* Lock the EEPROM: */

void LockEeprom(void)

{

   while ((FLASH->SR & FLASH_SR_BSY) != 0) /* Wait for FLASH to be free */

   {

/*   insert timeout test */

   }

   FLASH->PECR = FLASH->PECR & ~(FLASH_PECR_ERRIE | FLASH_PECR_EOPIE); /* disable flash interrupts */

   FLASH->PECR = FLASH->PECR | FLASH_PECR_PELOCK; /* Lock memory with PELOCK */

}

To read you can use a simple structure (eg called Eeprom_registers) and have something like:

#define CONFIG ((Eeprom_registers *) DATA_EEPROM_BASE_ADDR)

then get data using something like

Eeprom_data1 = CONFIG-> xxxx ; /* where xxxx is the entry in the Eeprom registers */

either that or something like

Eeprom_data1 = *(uint32_t *)(addr); /* where addr is the EEPROM address you want to read */

Hope this helps.