STM32F405RG is not pin compatible with other R series

I did earlier state that many of the STM32 series are pin compatible making it easy to scale up. I have to my surprice discovered that this is NOT true for STM32F405Rx versus other R series. I just mounted a F405 on a F103Rx design for testing and it did not work as expected. Paying more attention to the datasheet I realize that I have overlooked that some of the VDD pins have been renamed VCAP1 and VCAP2.

You will instantly notice a short-cut between 3.3V and GND. Well, this was a test and it did it’s purpose even if the outcome was unexpected. I have swapped F103 and F105 before, but this was the first time I checked out F405 before sending off designs using this.

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