How to code an ECG (Electrocardiogram) click 3 using STM32F446RE?

That it is cool the heart beat rate is OK . With the rest it will be hard, maybe tomorrow I will try some changes in library, I will let you know. But it will be probably about configuration, I think.
You can look into the init method in the library and if you know what you want then you can to set it - page 26+ of MAX30003 - datasheet

That blinking of RGB led, on the ST-link, mean St-link connection initialization. That seems like…

  • power source issue on USB port
  • broken USB cable
  • But probably… check this topic

You need to change the value in wait(3) (3sec) function. Normally it run much faster, maybe 100ms or something like that.

BR, Jan