Dear ST supporter, As i read STM32F042C4U6 datasheet. It have 16k flash. But I can write to sector 31 (every sector 1K). I also can view memory this sector from ST-link utility. Is it have 32K flash? thanks

[tpham.1]

..

[waclawek.jan]

Yes it's probably the same chip physically as the larger ones, it's just that part of the FLASH was not tested by manufacturer, so it's not guaranteed to work. You should treat it as it does not exist, if you don't want to run into trouble. In future, in the same product, that part of FLASH may be blocked in some way, or it may not exist at all.

JW

[Ozone]

> Yes it's probably the same chip physically as the larger ones, it's just that part of the FLASH was not tested by manufacturer, so it's not guaranteed to work.

I suppose it was tested, and found to not work properly.

[Tesla DeLorean]

That usually isn't the business dynamic of IC Test.

If they DON'T test sections of the IC they can significantly reduce the time on the tester, especially true of FLASH, USB, CRYPTO, etc. and run far more devices through the tester, which has a large amortized cost.

[Uwe Bonnes]

Otherwise, there many STM32F103x8 used with flashed data/programm above 64k and no problem has been reported so long, as long as it is a real STT32F103x8.

[waclawek.jan]

"no problem reported" [in working under unknown circumstances] is an entirely different assertion than "guaranteed to work" [in the whole stated operating envelope].

It's much like overcloking.

Some like it hot.

JW

[Uwe Bonnes]

I do not mean to use a STM32F103x8 as STM32F103xB in a commercial project. But for a hobby project is may be fine.