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Stm32F407VET6 Custom board Vcap1 and Vcap2 problem


I recently designed an stm32 board based on the stm32f4 I used a multimeter to test all the vdds and nrst everything is normal 3.3V but the vcaps only show 0.3V instead of 1.2V, what could be the problem? Can anyone help?


Are there proper capacitors connected to the VCAP pins?

Did you check *all* VDD/VSS pins, including VDDA/VSSA?

Did you measure *continuity* to GND/power supply? (i.e. many/most multimeters, when measuring voltage on GND pin, will show 0V regardless of whether they are actually connected to GND or not; that's why continuity (resistance) has to be measured).

Did you measure directly at the physical pins?



PS. A *very unlikely* option: if you for any reason used an ancient Rev.A chip, pin99 would be PDR_ON and has to be connected to VDD instead of VSS.