topic Re: LLWU Pin State in Kinetis Microcontrollers

LLWU Pin State

astdom01 — Wed, 05 Nov 2014 15:52:24 GMT

Dear all

I use an external pin triggered on any edge as wakup source of the LLWU. After wakup I need to figure out if it was a raising- or a falling-edge. When I use a pin as LLWU-Souce I can not use the same pin as GPIO-Pin anymore (CodeWarrior with Processor-Expert). What is the best practice to find out if it was a falling- or raising-edge which triggered the wakeup? I have 2 ideas:

Connect the signal to a second pin which I can use as GPIO-Pin and read the pin state after wakeup.
I dont see in the reference Manual that a LLWU-Pin can not be used as GPIO-Pin as well - but the Processor-Export UI does not allow it. Maybe I can configure the pin manually as GPIO pin and use it that way

Please let me know your intentions about this Problem.

Thank you, Dominic

Re: LLWU Pin State

Alice_Yang — Thu, 06 Nov 2014 02:33:06 GMT

Hi Dominic,

1) You can config the Wakeup Pin Enable for llwu for rising edge/falling edge/ any change in LLWU_PE register.

2) I recommend you use the first idea, also you can connect a led. Even thought the pin as LLWU , while the state of the pin we can also check .

Hope it helps

Alice

Re: LLWU Pin State

antonioconcio — Thu, 06 Nov 2014 08:15:49 GMT

Hi Dominic,

You have to enable the "pin sharing" setting in order to use the same pin as GPIO in PEx.

Please refer to this post HERE.

Hope that helps,

Antonio

Re: LLWU Pin State

astdom01 — Thu, 06 Nov 2014 12:48:25 GMT

Pin sharing works great!! Thank you :-)