3 years, 6 months ago.

NUCLEO F411RE LSE issues after installing HSE X3 xtal

Hello all, I just installed a 8MHz quartz with 22pF Capacitors for HSE on this nucleo board and it's working fine (checked with the MSO outputs).

The LSE was working fine before, but now is not starting.

I was very careful when soldering the X3 xtal and extra components, but as it's one of the first time that I'm soldering smd components I'm not very confident.

Has anybody been successful in installing the X3 crystal and having the X2 working too ?

The board revision in the C03.

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2 Answers

3 years, 6 months ago.

In file stm32f4xx_hal_rcc.h (replace MBED library with MBED-DEV library).


You will find line 1220

define RCC_LSE_TIMEOUT_VALUE ((uint32_t)5000) /* 5000 ms */

Change the LSE timeout value from 5000ms to 500ms

define RCC_LSE_TIMEOUT_VALUE ((uint32_t)500) /* 500 ms */

The 32KHz oscillator does take a longer time to lock, but 5000ms is rather a long time. Surprised it worked in the first place.

I'm using F401 but uses the same library code

Hi Paul, I'm using mbed-dev and did try every possible value for the RCC_LSE_TIMEOUT_VALUE from lower values to bigger values.

I'm starting to think that the problem is HW related, and maybe I broke the X2 capacitors during soldering with a ESD discharge... I ordered new caps and new crystal to change them, let's see if I fix it.

I'm getting an EPSON quartz with 6 pF CL, 4.7 pF and 2.2 pF to experiment. And I'll check my ground connections to the mains as my soldering station should be ESD safe (an OKi/Metcal PS-900).

posted by Riccardo Ascenzi 17 Mar 2016
3 years, 6 months ago.

I think this is a big issue for Nucleo mbed board.
If above answer is not enough for your case, please refer my note for your next step.
You can check start up time for LSE(32.768kHz Xtal) using following program.

Import programNucleo_RTC_Clock_setting

Check RTC LSE(External Xtal, 32.768kHz) mode

Hi Kenji, your work was very useful to understand the nature of the issue, thanks again ! I used that sketch to measure the startup time before soldering X3 and it was around 400ms, now it always timeouts.

As I wrote to Paul I'm starting to think it's an HW issue, I'll make some new tests.

Thanks again !

posted by Riccardo Ascenzi 17 Mar 2016