Migrate from STM32F401CCUx to STM32F103C8T6

[FDragon_21]

I've done a long search on the Internet but only found the migrated STM32F103 to the STM32F4 series, not vice-versa. So I'm asking anyone who can help me. To be specific I am going to try this project from GitHub but in my case, I'm going to use STM32103C8T6. I hope you can help. Thanks.

here the project link: 
GitHub - tvlad1234/pillScopePlus: Oscilloscope based around the STM32F401 Black Pill and a color LCD screen

[Uwe Bonnes]

STM32F1 is year older and  less capable than STM32F4. So it will be hard work to rework the F4 code to work on a F1.AN4904 for migrating from STM32F1 to STM32F4, not the other way round.

[Peter BENSCH]

There is a good reason why the user of that Github project used the STM32F401 for his project and not the STM32F103: at least the performance of the CPU supplemented by a significantly faster ADC, as @Uwe Bonnes already mentioned. In addition, the STM32F103 is still based on a Cortex-M3, which has long since ceased to play a role and has been replaced by the significantly better Cortex-M4. The Cortex-M7, which appeared afterwards and forms the heart of families such as the STM32F7 or STM32H7, offers even more oomph.

I also would strongly recommend staying with the STM32F401 and possibly thinking about switching to the STM32H7 at a later date.

Regards
/Peter