STM32F407 TIM2_CH1_ETR

[ari239955]

Posted on August 20, 2014 at 20:00

Maybe this is explained somewhere in the RM, but because I didn't find the answer with a brief study I will try if the forum can help...

So the question is about the alternate function pin named TIM2_CH1_ETR. I want to use this pin as the second interface to an incremental encoder (the other is TIM2_CH2), but this extra ETR suffix confuses me a bit. If I understand correctly ETR stands for external trigger, which actually I don't need in my application. So somehow the ETR function and normal TIM2_CH1 capture input are multiplexed to the same pin, but is it possible to configure the timer such a way that the ETR function is not used?

[Tesla DeLorean]

Posted on August 20, 2014 at 20:05

Share functionality, as ETR only operates in input mode it won't clash with CH1 in or out functions.

[ari239955]

Posted on August 20, 2014 at 20:39

Hi Clive,

And thanks for the prompt reply!

Just to clarify, as I already use CH1 in input mode, but I can configure the timer such a way that ETR doesn't affect the operation, right?

[Tesla DeLorean]

Posted on August 20, 2014 at 23:06

It won't interfere, to use it as an ETR input you'd need to configure one of the External Count modes.