AnsweredAssumed Answered

STM32F407's Clock is not working

Question asked by chu.Yd on Mar 14, 2017
Latest reply on Mar 16, 2017 by Clive One

dear. Engineer sir


We are currently working on a project using the STM32F407ie UFBGA176 chip.

After configuring the microcontroller on the PCB and checking the operation of the microcontroller, the external oscillator clock will not work.

We have confirmed that there is no problem with the power pin and reset circuit.

So I checked the circuit and found that nothing was connected to the BYPASS_REG and PDR_ON pins.

In our current PCB, there is no way to connect these two pins because BYPASS_REG pin and PDR_ON pin are not exposed.

What is the default value when nothing is connected to the BYPASS_REG and PDR_ON pins?

When I looked at the data sheet, I noticed that the VCAP_1 and VCAP_2 pins were connected to the out portion of the regulator.

Is it possible to connect from outside through this part?

Or if there is a way to run the clock without using the BYPASS REG and PDR_ON pins

What is the reset controller associated with the PDR_ON pin?

And if there is a way we do not know except for the above method, I would appreciate if you could suggest it. please


Thank you