Stm32F407VET6 Custom board Vcap1 and Vcap2 problem

[PChat.4]

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?

[waclawek.jan]

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?

JW

 

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.