STM32F072C8 Total Flash Memory?

[Hi world!]

Hi guys,

The STM32F072C8 microprocessor has a total of 31 flash pages. Each page is 2 kb in size. Thus, the processor has 64 (2x32) kb flash memory. The interesting thing is that I can read / write on page 63. How is that possible?

Thanks.

[Uwe Bonnes]

STM32F072x8 and STM32F072xB have the same datasheet, the same MCUID and so the same die. So it means upper flash is on the chip. Some chip may get the STM32F072x8 marking when

• perhaps upper flash tested bad
• perhaps upper flash was not tested at all
• perhaps when market pressure requires to mark good xB chips as x8
• perhaps some non reversable fuse disables upper flash

What really happens is ST secret.

[Hi world!]

Thanks for reply.

I also think like you. The odd thing is that after page 31, writing and reading is only possible with the program. For example, I can't write there with ST Link Utility.

[Uwe Bonnes]

If the programmer reads out the flash size register, it can disallow write above the indicated flash size register. The same happens with "well-havehaving" DFU adapters. Try e.g. https://github.com/blacksphere/bl*ckm*g*c/wiki with the pc-stlinkv2 platform and it should work.

[Tesla DeLorean]

The Utilities read a value written in OTP indicating how much was tested, and how product was marked.

Test time for flash is significant. If they test only half, they can have approx twice the throughput on the equipment.

[Hi world!]

Thanks for reply.

You misunderstood me. I have no problem with St Link-utility. My problem: Stm32f072c8t6 I can write and read on page 63 with the flash functions that I have written in keil. I mean, how come I can get there? Is this normal? Because stm32f072c8t6 has 64 kB of flash memory. But I can read and write on page 63. (Each page is 2 kB in size)

[Tesla DeLorean]

>>I mean, how come I can get there?

ST makes one die that has 128KB FLASH on it, and can sell that as a 64KB or 128KB version.

Is this really that hard to understand?

[Hi world!]

I know what you're saying, of course. I'm not asking about her.

The processor I use is 64 kB (stm32f072c8t6). Flash pages are 2 kB in size and have 32 flash pages. (2x32 = 64kB)

But I can read and write data on page 63 of this processor. How is that possible?

[Ozone · Accepted solution]

Because it' actually a 128k Flash device, but there is a defect somewhere in the upper 64k.

ST will retreat to guaranteed values & sizes in the datasheet, and beyond that, you are on your own.

[Hi world!]

That's what I meant. I was wondering why I could use it. As you say then there is no guarantee for over 64 kB.

Thank you.