backup RAM for STM32H743 device

[Anand Ram]

according to the manual it says 4 Kbytes of backup SRAM in D3.

D3 start address is 0x38000000

in manual address for backup RAM is 0x3880 0000

but below is the behavior observed.

code example.

 __HAL_RCC_BKPRAM_CLK_ENABLE();

 HAL_PWREx_EnableBkUpReg();

 HAL_PWR_EnableBkUpAccess();

by the above code, i can retain the data at address 0x38000000 after the soft reset.

can somebody explain the reason for this.

[Pavel A.]

0x38000000 is the D3 SRAM (64 KB)

-- pa

[TDK]

> by the above code, i can retain the data at address 0x38000000 after the soft reset.

A soft reset (i.e. a reset without loss of power) won't erase any RAM.

The backup ram can be powered from VBAT which makes it possible to be retained if VDD is lost but VBAT remains.