STM32F407VET6 has 1MB flash !

Limited support for STM32F4 Discovery, Nucleo and custom F4 boards
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Re: STM32F407VET6 has 1MB flash !

Post by victor_pv » Fri Aug 25, 2017 7:11 pm

BulbChangeExpert wrote:
Fri Aug 25, 2017 4:55 pm
there are VG and VQ ... from both Korea and Philippines (the PHL on mine or KOR on the internet (or China (CHN) and Malaysia (MYS) on my blue pills)), that's what google images displays
I have at least 3 or 4 F4 by now, I think I checked the flash size in one of them, by trying to read and write past 512KB. In the F1 stlink will write past the reported address if the mcu actually has more, but perhaps that fails in the F4 and the loader is able to read and write to it?

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Re: STM32F407VET6 has 1MB flash !

Post by BulbChangeExpert » Fri Aug 25, 2017 11:20 pm

i used via FT232

it apparently can calculate, read and write the real memory without taking into account IDs and stuff, you can even burn past a bootloader (specifying a start address)

but the ST Link Utility (the actual GUI program) can read the whole memory, it can even (un)protect all the sectors, if you set "Size" at 0x100000 it will read the whole, you can't modify the bonus part but if you try to input something like 0x100100 it wil not read past 0x100000

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Re: STM32F407VET6 has 1MB flash !

Post by victor_pv » Sat Aug 26, 2017 2:21 am

I just checked 2 of my F407VET boards with a jlink and ozone, and both had 1MB :)
Not sure how I checked the other time, but perhaps I did something wrong.
Nice to know there is a whole 512KB extra in those.

I also checked CCM RAM and SRAM, and could only read 64KB and 128KB respectively on both boards.

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Re: STM32F407VET6 has 1MB flash !

Post by Pito » Sat Aug 26, 2017 10:03 am

That is because some vendors recognized the Cost of MCU "fabrication" (not counting here R&D) of smaller sram/flash chips are the same as of the bigger one, but their Marketing people say they have to offer a variety of chips to make customers happy.

The costs of chip's cutting/bonding/assembly/testing/packaging are much higher than the production cost of a Silicon wafer (the chip foundries charge usually flat fee for a wafer) therefore messing with many chip types is much costly than to mess with a few one. The single chip (die) on a 300mm wafer could cost $0.25-$0.5 (based on the STM32 chip size), while you get 3k-6k chip dies (working) off the wafer.

The Masks (or "the chip tapeouts", the masks are used for the UV lithography process, you need 20-36 of them today in order to produce an MCU/CPU) are the most expensive production cost item - they have to be refreshed from time to time and their production costs are high (a set of masks for 90nm node - ie STM32F407ZG - may cost about $0.5-1mil).
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