Accessing outside flash area is working...

[HHaga.1]

Tested to flash a 128k (STM32F105) device with a firmware (40k) that is compiled for 256k and it works. Even when the firmware reads and writes data (config) to address location 0x0083E000 which is way out of the 128k device memory area.

Is there some type of virtual address that points to the 0x0081E000 location when going out of flash bounds??

regards,

[KnarfB]

see https://community.st.com/s/question/0D50X00009XkWnp/stm32f105rb-flash-range

[HHaga.1]

Aha, that exaplains why it still works!

So the memory is still there on the 128k version but it may not passed the memory test at factory...

[Tesla DeLorean]

Failing is a thing of myth/folklore, in IC Test the cheapest test is to not test at all.

If there is some egregious failure where the current is outside expectations, or critical paths that fail stress testing, this will be known early into the test vectors.

The flash memory tests would be one of the most time consuming thing to do on test equipment amortized by the hour. ST offers feature reduced parts where portions of the die are simply not tested, ie USB, Ethernet, Flash, etc.

They do have a mix of die, but it's not one per SKU