Bug with Cube, 4.21 and F7 AHB1 timer clock

[Uwe Bonnes]

Posted on May 17, 2017 at 10:57

Hello,

it seems cube does not take care of time TIMPRE x4 multiplier for the AHB1 timer clock

Note: this post was migrated and contained many threaded conversations, some content may be missing.

[Nesrine M_O]

Posted on May 17, 2017 at 11:39

Hi

Bonnes.Uwe

,

Please make sure that theTIM Prescaler selection is enabled from RCC configuration tab:

-Nesrine-

[Uwe Bonnes]

Posted on May 17, 2017 at 12:30

Dear Nesrine,

thanks for the hint. However when setting the frequency field for AHB1 timer clock to 200 Mhz, cube tries hard to find a solution, but does not come up with the  'TIM Prescaler selection from RCC configuration'.

[Nesrine M_O]

Posted on May 17, 2017 at 14:39

Hi

Bonnes.Uwe

,

I' am not able to reproduce the issue that you describe :

• when the TIMPRE bit in the RCC_DCKCFGR1 register is set, if APBx prescaler is 1,2 or 4, then TIMxCLK = HCLK, otherwise TIMxCLK = 4x PCLKx.

• When TIMPRE bit of the RCC_DKCFGR1 register is reset, if APBx prescaler is 1, then TIMxCLK = PCLKx, otherwise

  TIMxCLK = 2x PCLKx

Could you please share your *ioc file for check?

-Nesrine-

[stm32cube-t]

Posted on October 19, 2017 at 14:42

Hello,

Please note the following feature on CubeMX clock tree. By right clicking the clock tree, you can lock a value you want to remain unchanged (HCLK here), then to reach 200MHz for the timer the timer pre-scaler will be adjusted fine.

[Beep]

I'm also finding this problem.  I suspect the HAL lib code doesn't take the TIMPRE setting into account and thus it calculates the wrong divider settings for the timer.