STM32F746G-DISCO, FLASH

[AD�?b]

Why does flasch memory lose saved data after being read and written after power off?

Andrzej

[KnarfB]

Sorry leader, but this is too little information. I'm using 20+ of those boards for years and they never did that to me.

[AD�?b]

Hi

I want:

1.Read the value from FLASH after power on

2. After aborting, save the current value in FLASH

I am doing:

1. my variable is uint32_t total_time; // save to FLASH in 87

2. I read total_time = * (__ IO uint32_t *) FLASH_SECTOR_4; // reading from FLASH at 180

3.unlock FLASH HAL_FLASH_Unlock (); // FLASH unlock for writing in 181

4. in the interrupt I write the variable

void HAL_GPIO_EXTI_Callback (uint16_t GPIO_Pin) // interrupt for writing to FLASH

{ if (GPIO_Pin == STOP_Pin)

HAL_FLASH_Program (FLASH_TYPEPROGRAM_WORD, FLASH_SECTOR_3, total_time); // saving to FALSH

} in 1005

Almost every time I read a different recorded value after turning on the power.

Andrzej

I include main.c

[KnarfB]

FLASH_SECTOR_4 != FLASH_SECTOR_3 ?

[AD�?b]

I changed:

total_time = * (__ IO uint32_t *) FLASH_SECTOR_3; // reading from FLASH It still does not work

[Tesla DeLorean]

Do you erase it? Do you look at the error codes?

How about you write incrementally, deeper into the sector, so you don't have to erase at every cycle ?

[AD�?b]

Do you erase it? No

Do you look at the error codes? No

How about you write incrementally, deeper into the sector, so you don't have to erase at every cycle?

I prefer to erase the entire sector one time.

But I do not know how to do it.

[KnarfB · Accepted solution]

> Do you erase it? No

Programming can only flip 1 bits to 0 bits. Erase is needed for the other way round. Why do you expect it to work without erase?

[AD�?b]

I want to erase but I don't know how.

[Tesla DeLorean]

STM32Cube_FW_F7_V1.16.0\Projects\STM32746G-Discovery\Examples\FLASH\FLASH_EraseProgram