how to can I reduce the noise radiated from STM32? Does that noise exists to all ST's controllers?

[panatronic]

I am using STM32F030K6T6. My project is a 433MHz one way data link. The RF receiver blocked from the radiated noise of STM32. So, the distance is reduced between the link. In order to make it work, RF receiver and STM32 have to be at least 5 inch far away but unfortunately this can not be done in real PCB as it must be compact (RF+controller). I need something to reduce the noise radiated from STM32 otherwise I have to replace the ST controller.

[LMI2]

"The only way to get rid of the noise is to place the RF module at least 5 inch away where it start to work" Can you place CPU and module at the opposite sides of the PCB? Biggest components anyway. Where was your shield? Have you filtered supply lines too. Put some more filters. Have you any RF measuring equipment, you could try to measure what leaks.

[LMI2]

And It looks like you have bad luck and have to think your project as a radio and not a MCU project. Use shields, ferrites and filter everything.

https://hackaday.com/2015/02/02/get-serious-with-amateur-radio-design-build-a-single-sideband-transceiver-from-scratch-part-1/

[Danish1]

Is your microcontroller doing anything with its I/O pins when you find you have to put it 5 inches away?

If it is (even as simple as flashing an LED, or worse communicating with your 433 MHz module), be aware that sharp output switching generates RF interference. This may be reduced by setting the output speed to a slower value i.e. GPIOx_OSPEEDR to GPIO_SPEED_FREQ_LOW for each output pin.

This reduces the slew rate so the pin takes longer to reach its new level.

Hope this helps,

Danish

[panatronic]

I placed the module at the opposite side of the PCB unfortunately, without success.

I haven't any RF measuring equipment but there is an old device with an antenna probe which measure the signal strength from any transmitter at 433MHz. When the probe of this device is placed close to STM32 (about an inch or less) the analogue panel meter shows the existence of low signal. I made that test with and without the RF module in place.

All the pins of STM32 are double checked. The speed for all pins is low. Unused pins are output and low state. 

The demand is to light a LED during reception. However, for testing only, I turned off this option without any success.

Finally, I switched to another MCU and there is an amazing difference. I removed capacitors, inductors and shields. Also, power consumption dropped to 4 mA.

Thanks all of you for your replies.

[T J]

which MCU did you try ?

[panatronic]

I migrated to STM8L151K6. It is slower than STM32 but I think I can optimize my code in order to reduce the latency.