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UART4 and SDIO in STM32F103RCT6

Associate II

Fix the stm cube, as these features do not work at the same time.

I lost a lot of time and money while I figured it out


Probably a good reason not to use 13-year old parts in a new design..

The peripheral/pin muxing method lasted one design iteration.

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Up vote any posts that you find helpful, it shows what's working..

It could be still worthwhile to display a warning in the CubeMX pin editor, instead of subtly punishing developers who do not turn to the errata reflexively.

While we might sometimes think that an ignorant developer deserves it, punishing does not make much sense from a business standpoint 🙂

Tell me, please, which microcontroller can I use? I need 4 UART and the ability to connect a micro SD card (SDIO or any)

Cube has a MCU selection tool where you can search and filter the available MCUs. Judging by your original MCU you want a LQFP64 part. You can use STM32F412RE or STM32F446RE for example.

I use the cube mix just for configuration. So his cost is 4 times more expensive.

STM32F401RB / STM32F401RC are less expensive, but they have 3 USARTs, you can use it and software-emulate the remaining one. Or software-emulate in your STM32F1.


Check out the STM32L451RCT6. Same amount of memory, more flexible pinout, slightly faster core, and costs less.

If you'd like to keep the STM32F103RCT6, you can still communicate through SPI with the SD card, if the speed is not critical.

Associate II

I think, I will use DeInit SDIO to use UART, if i need data from sd card, will be init SDIO again

Hi @berendi​ ,

Your proposal is shared with our STM32CubeMX team.


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