STM32L0 vs STM32F0 huge difference in base code size

[Anders Dam Kofoed]

Posted on December 11, 2016 at 11:25

HI All,

I am wondering why initial code size differs with a factor of 3 between the STM32F031K6 and the STM32L031K6 - just for making an LED blink.

I use CubeMx to generate the project and GCC (OpenSTM32 AC6 IDE) to compile it. In CubeMX I select the Nucleo-F031K6 and the Nucleo-L031K6 and click the 'Initialize all peripherals with their default mode'. Then I leave everything as default, just enough to make the LD3 blink (PB3).

Compiling the project without any modification gives me the following code size:

== STM32L031K6 ==

arm-none-eabi-size 'TEST-L0.elf'

text data bss dec hex filename

12504 12 1684 14200 3778 TEST-L0.elf

== STM32F031K6 ==

arm-none-eabi-size 'TEST-F0.elf'

text data bss dec hex filename

4536 12 1684 6232 1858 TEST-F0.elf

== Question ==

Why this huge difference in code size between the L0 (12,5 KB) and the F0 (4,5 KB) ?

Kind regards

Anders

[Seb]

Posted on December 11, 2016 at 11:56

Most compiler toolchain can generate a MAP file which details for each *.o object file the used memory for constants, code and variables. It should help to analyse the resulting code size.

Good luck!

[Tesla DeLorean · Accepted solution]

Posted on December 12, 2016 at 20:46

Review .LD and .MAP files

The linker script might separate regions leaving holes, the .MAP file should break down what's where. A disassembly listing might also be instructive.

Review optimization setting, and libraries pulled in.

One complaint and possible cause is if one is pulling the floating point code library, vs one not. The code to compute the USART baud rate has some unnecessary floating point computation in one of the HAL releases.

#dogfooding

‌

[Oliver Beirne]

Posted on December 13, 2016 at 16:24

Hi

Kofoed.Anders_Dam

I have moved this post to the

https://community.st.com/s/topic/0TO0X000000BSqSWAW/

where product related questions are posted.

Thanks

Oli

[Anders Dam Kofoed]

Posted on December 13, 2016 at 16:33

Thanks Cilve,

Yes, disabling the USART driver gave me this:

== STM32L031K6 ==

arm-none-eabi-size 'TEST-L0.elf'

text data bss dec hex filename3608 12 1572 5192 1448 TEST-L0.elf

== STM32F031K6 ==

arm-none-eabi-size 'TEST-F0.elf'

text data bss dec hex filename3296 12 1572 4880 1310 TEST-F0.elf

The L0 slightly bigger than the F0. Also you are right in that it seems to include code that does some multiplication or division...

Thanks

Kind regards

Anders

[Tesla DeLorean]

Posted on December 14, 2016 at 21:46

https://community.st.com/0D50X00009XkflfSAB

 

https://community.st.com/0D50X00009XkaFMSAZ