How to enable/disable Flash Write Protection?

[Junde]

Hi guys,

I am read the example "STM32Cube_FW_F1_V1.8.4\Projects\STM32F103RB-Nucleo\Examples\FLASH\FLASH_WriteProtection", and want to rewrite it on my board.

my code is as follows:

 

 HAL_FLASH_Unlock();
 HAL_FLASH_OB_Unlock();
 
 HAL_FLASHEx_OBGetConfig(&OptionsBytesStruct);
 LOG_DBG("current config: WRPState[%d]\n", OptionsBytesStruct.WRPState);
 LOG_DBG("current config: WRPPage[0x%08x]\n", OptionsBytesStruct.WRPPage);
 if((OptionsBytesStruct.WRPPage & FLASH_PAGE_TO_BE_PROTECTED) == FLASH_PAGE_TO_BE_PROTECTED) { // if WRP enable
 LOG_DBG("Flash is WriteProtection\n");
 OptionsBytesStruct.OptionType = OPTIONBYTE_WRP;
 OptionsBytesStruct.WRPState = OB_WRPSTATE_DISABLE;
 OptionsBytesStruct.WRPPage = FLASH_PAGE_TO_BE_PROTECTED;
 if(HAL_FLASHEx_OBProgram(&OptionsBytesStruct) != HAL_OK) {
 LOG_ERR("Flash OB program err when turn WRP off\n");
 }
 HAL_Delay(10000);
 LOG_DBG("system reset\n");
 HAL_Delay(1000);
 HAL_FLASH_OB_Launch();
} else {
 LOG_DBG("Flash is NOT WriteProtection\n");
 OptionsBytesStruct.OptionType = OPTIONBYTE_WRP;
 OptionsBytesStruct.WRPState = OB_WRPSTATE_ENABLE;
 OptionsBytesStruct.WRPPage = FLASH_PAGE_TO_BE_PROTECTED;
 if(HAL_FLASHEx_OBProgram(&OptionsBytesStruct) != HAL_OK) {
 LOG_ERR("Flash OB program err when turn WRP on\n");
 }
 HAL_Delay(10000);
 LOG_DBG("system reset\n");
 HAL_Delay(1000);
 HAL_FLASH_OB_Launch();
 }

 HAL_FLASH_OB_Lock();
 HAL_FLASH_Lock();

 

The output is as this:

 

Flash Write Protection demo...
current config: WRPState[0]
current config: WRPPage[0xFFFFFFFF]
Flash is WriteProtection
system reset

Flash Write Protection demo...
current config: WRPState[0]
current config: WRPPage[0xFFFFFFFF]
Flash is WriteProtection
system reset

Flash Write Protection demo...
current config: WRPState[0]
current config: WRPPage[0xFFFFFFFF]
Flash is WriteProtection
system reset

 

What I expected of the output should be like "WRP_EN --> WRP_DIS -->WRP_EN --> WRP_DIS ......".

I have no idea what I was wrong, help me, please. 

Thank you.

 

BTW, I am confused about the result of "HAL_FLASHEx_OBGetConfig(&OBStruct);", if the result as below:

 

 HAL_FLASHEx_OBGetConfig(&OptionsBytesStruct);
 LOG_DBG("current config: WRPState[%d]\n", OptionsBytesStruct.WRPState); // 0
 LOG_DBG("current config: WRPPage[0x%08x]\n", OptionsBytesStruct.WRPPage); // 0xFFFFFFFF

 

Then, does that mean all the flash is WRP, or all the flash is NOT in WRP?

Thanks again for your help in advance.

 

[FBL]

Hello @Junde 

Referring to PM0068, you can check write protection definition (0 for activated WRP). 

[Junde]

@FBL Thanks for your help.

I was wrong about the meaning of the FLASH_WRPR bit.(0 is for active, NOT 1)

So my code should be as this:

 HAL_FLASH_Unlock();
 HAL_FLASH_OB_Unlock();
 
 HAL_FLASHEx_OBGetConfig(&OptionsBytesStruct);
 LOG_DBG("current config: WRPState[%d]\n", OptionsBytesStruct.WRPState);
 LOG_DBG("current config: WRPPage[0x%08x]\n", OptionsBytesStruct.WRPPage);
 if((~OptionsBytesStruct.WRPPage & FLASH_PAGE_TO_BE_PROTECTED) == FLASH_PAGE_TO_BE_PROTECTED) { // if WRP enable
 LOG_DBG("Flash is WriteProtection\n");
 OptionsBytesStruct.OptionType = OPTIONBYTE_WRP;
 OptionsBytesStruct.WRPState = OB_WRPSTATE_DISABLE;
 OptionsBytesStruct.WRPPage = FLASH_PAGE_TO_BE_PROTECTED;
 if(HAL_FLASHEx_OBProgram(&OptionsBytesStruct) != HAL_OK) {
 LOG_ERR("Flash OB program err when turn WRP off\n");
 }
 HAL_Delay(10000);
 LOG_DBG("system reset\n");
 HAL_Delay(1000);
 HAL_FLASH_OB_Launch();
} else {
 LOG_DBG("Flash is NOT WriteProtection\n");
 OptionsBytesStruct.OptionType = OPTIONBYTE_WRP;
 OptionsBytesStruct.WRPState = OB_WRPSTATE_ENABLE;
 OptionsBytesStruct.WRPPage = FLASH_PAGE_TO_BE_PROTECTED;
 if(HAL_FLASHEx_OBProgram(&OptionsBytesStruct) != HAL_OK) {
 LOG_ERR("Flash OB program err when turn WRP on\n");
 }
 HAL_Delay(10000);
 LOG_DBG("system reset\n");
 HAL_Delay(1000);
 HAL_FLASH_OB_Launch();
 }

 HAL_FLASH_OB_Lock();
 HAL_FLASH_Lock();

 

[Georgy Moshkin]

Checking WRPState is useless, because this field is never set in HAL_FLASHEx_OBGetConfig() function:

 

void HAL_FLASHEx_OBGetConfig(FLASH_OBProgramInitTypeDef *pOBInit)
{
 pOBInit->OptionType = OPTIONBYTE_WRP | OPTIONBYTE_RDP | OPTIONBYTE_USER;

 /*Get WRP*/
 pOBInit->WRPPage = FLASH_OB_GetWRP();

 /*Get RDP Level*/
 pOBInit->RDPLevel = FLASH_OB_GetRDP();

 /*Get USER*/
 pOBInit->USERConfig = FLASH_OB_GetUser();

 /* WRPState was never set! */
}

 

You can only rely on WRPPage, RDPLevel and USERConfig fields.

WRPState is only useful when you set OBInit.WRPState to OB_WRPSTATE_EBABLE or OB_WRPSTATE_DISABLE and then feed OBInit to the HAL_FLASHEx_OBProgram().