Fill value in auto checksum (CRC) calculation

[Clonimus74]

Posted on August 29, 2016 at 20:46

Hi all,

In the

https://www.iar.com/support/tech-notes/general/calculate-crc32-as-in-stm32-hardware-v.5.50-and-later/

they instruct to fill unused ROM with 0xFF, is is arbitrary or is there some logic to it?

The reason I ask is that if I fill it with 0x00 (as the erase flash value is) I don't have to waste time programming empty space in bootloader update.

I leave the ROM range at max in the

IELFTOOL tool (and bootloader crc verification function) because I have no idea how large the application might be in the future.

Thanks

#ielftool-checksum-stm32 #crc

[Walid FTITI_O]

Posted on August 30, 2016 at 11:09

Hi Clonimus74, 

Check the

https://www.iar.com/support/tech-notes/general/calculate-crc32-as-in-stm32-hardware-v.5.50-and-later/

of IAR SYSTEMS which describes how to calculate CRC32 in STM32hardware.

-Hannibal-

[Clonimus74]

Posted on August 30, 2016 at 11:26

The link you shared is the same one I put in the OP, and it doent answer my question.

Is filling the unused flash area with 0xFF is arbitrary or is there a reason not to use 0x00 which is the value it has after erase operation (in STM32L151)?

[so to simplify the bootloader process].