[STM32F413RHT6] Clock speed problem

[nicolas b]

Posted on April 05, 2018 at 10:56

We are trying to increase the clock speed of our STM32 on our custom board but we encountered some difficulties.

At the moment, we set a clock of 56 MHz, using HSI and an PLL of 112 (with CubeMx). It works fine.

But when we set a clock of 96 MHz by setting the PLL to 192, we get Hard Fault, Usage Fault or Bus Fault when debugging.

We tried increasing the flash latency, but it does not work better. The power supply seems good (around 3,2 V).

We were missing the Vcap on the board, but we fix that. Not better.

What can we look at to debug this problem ?

#cpu-clock-frequency

[T J]

Posted on May 18, 2018 at 01:30

NRST is not connected in your diagram ??

I use a reset chip on NRST, MIC803 triggering at 2.9V for 1.2Sec.

NRST requires a 0.1uF and a 10K or 1K pullup.

VCap 2 also requires the Low ESR 2.2uF

[Adam I.]

Posted on May 18, 2018 at 13:43

In my application, an internal POR / PDR is enough.

The NRST pin is internally pulled 40k, so an external resistor is not needed in most cases.

I have connected 0.1uF to ground (error in the diagram above).

I would highly recommend AN4488: Getting started with STM32F4xxxx MCU hardware development.

[nicolas b · Accepted solution]

We did a second version of our design with a more stable power supply and it seems to fix the problem.

Thank you all for your help.