STM32F407 Specs

[masoudr]

Hi, First I need to say thanks for this library. I think for STM32F4 familly it is the best arduino framework in comparison with other libraries. As you may know The STM32F407VET6 chip has 192KB of ram but when I compile my code I see 128K. Here is the output of arduino application:

Sketch uses 17748 bytes (3%) of program storage space. Maximum is 524288 bytes. Global variables use 3920 bytes (2%) of dynamic memory, leaving 127152 bytes for local variables. Maximum is 131072 bytes.

I found the port to Atom application from here. And I think it shows the true value:

Building .pioenvs\black_F407VE\firmware.bin Memory Usage -> http://bit.ly/pio-memory-usage DATA: [ ] 2.0% (used 4016 bytes from 196608 bytes) PROGRAM: [ ] 3.7% (used 19636 bytes from 524288 bytes) [SUCCESS] Took 3.62 seconds

Is there any diffrence of STM cores between these two apps? Is there any limits or it is a simple faulty compiler message? Thanks.

[ChrisMicro]

Did you choose the correct MCU variant in the menu? As far as I know the memory definitions in the linker file are responsible. It seems that the RAM is set to 128K there: https://github.com/danieleff/STM32GENERIC/blob/master/STM32/variants/BLACK_F407VE/ldscript.ld

[masoudr]

Thanks. The only correct option is "Black F407VE (V2.0)". I edited the ldscript.ld and changed the RAM value. But It still shows the same message and FYI the Atom port uses the exact same files so ldscript.ld is same. I think the problem is somewhere else maybe compiler is the problem.

[burner-]

Looks that this is not so straight forward thing. There is article what explain why it is 128kB instead on 192kB https://jeelabs.org/2018/z80-zexall-f407/