STM32MP157 input capture gives wrong value

[alex_vm]

Hello,

 

I've tried measure period of  GPS PPS which is very high accuracy. I'm using TIM5 input capture mode, reset slave mode. The TIM5 CCR1 gives value 208877646 that is wrong because I use high accurate generator for sys clock. The right value is about 209000000. So maybe anyone meet the problem?

 

Thanks,

Alex.

[PatrickF]

Hi @alex_vm ,

could you check the real TIM5 clock using :

 grep -E "clock|tim5_k" /sys/kernel/debug/clk/clk_summary

in starter package, the clock is defined as 208877930Hz, so your results sound good with this value (tolerance of HSE oscillator).

Regards.

[alex_vm]

Hi Patrick

Thank you for your help. I forget to write in the start topic I'm using M4 in standalone mode .But as I think the cause is a same.

BR