STM32L4R5ZI - Is it possible to erase a page and write a double word in Flash ?

[KVenk.1]

Hi,

I am using STM32L4R5ZI MCU (Nucleo kit). My application demands non-volatile storage of few configuration parameters. I am using 2 banks mode. I want to store a double word at location 0x8100000 which is first page of bank 2. I tried the STM32L4R5ZI_NUCLEO_FLASH_EraseProgram example code that was available from ST webpage. But am getting unpredictable results. Sometimes It works. But most of the times, Erase operation was not successful. All I was trying is, ensure the double word is properly saved at first page of the 2nd bank everytime i write with new value. Why there is inconsistency in erasing the flash memory ?

[Tesla DeLorean]

>>Why there is inconsistency in erasing the flash memory ?

Hard to know, guessing implementation or power stability

Saving / updating configuration structure in FLASH on the L4R5 here, also doing firmware updating, not sure why your implementation fails.

Supply on NUCLEO should be fine.

[KVenk.1]

I observed that, controller boots from System memory whenever there is erase failure. I got this by noticing controller not stopping at the breakpoint during debug. When i hit pause, ide flags "Break at address 0x1ffffxxxx with no debug information available, or outside of program code" . This confirms that controller is not booting from the flash memory. I verified the BOOT0 pin voltage level and it is as expected 0V. Then I verified the OPTR register value for nBoot1 and nBoot0 bit status. I could see nBoot1 bit is set, but in SFRs view, I couldnt see nBoot0 value. Why the controller is booting from system memory occassionally ? This is not happening everytime. When I recompile and again debug, it boots from flash memory.

[TZARDI]

​Hello,

Verify the value of nSWBOOT0 if it's set, with the BOOT0 is 0 and when the flash is empty the system will boot from the system memory. You can check table 4 Boot modes of the reference manual  to see the different boot possibilities.

Br,

[KVenk.1]

Yes, nSWBOOT0 is set. But how it considers Flash empty, because am just modifying the configuration value that needs to be written on Page 1/Bank2.

[TZARDI]

​Hello,

Can you share the configuration of the FLASH_OPTR register and your main if it's possible? I want to check if the bit BFB2 is set or not.

Br,

[KVenk.1]

HI,

Pls find snapshot of the FLASH register below , taken in debug mode: BFB2 is RESET, so dual bank boot disabled.

[KVenk.1]

[TZARDI]

Hello,

Can you maybe share your main? I tried the example but i couldn't see the problem you're facing.

Br,