FTM Input Channel Direction

[davidwightman]

I am using an input capture FTM channel on the iMX7.  Inconveniently it seems to initialize as an output and only switches to an input when the channel interrupt is enabled, irregardless of the CnSC setting.

On the FTM in the Kinetis platform, if the CnSC register was set to 0, then the pin would go to the GPIO state.  This is the described behavior in the iMX7 reference manual too, but I haven't observed this.  I guess because of the pad muxing on the iMX7, the FTM channel turns into an output instead. 

Can anyone confirm this behavior? 

[art]

The direction and behaviour of the FlexTimer Channel signals is completely controlled by the corresponding FTMx_CnSC register settings regardless of whether the channel interrupt is enabled or not.

I think the possible cause of the issue is inappropriate configuration of a channel signal routing in the IOMUXC controller. So, please check the corresponding IOMUXC SELECT_INPUT and SW_MUX_CTL registers for selected channel signal IOMUX routing scheme. For details, please refer to the Section 8.2 "IOMUX Controller (IOMUXC)" of the i.MX7 Reference Manual document, available on the processor's Documentation web page:

https://www.nxp.com/products/processors-and-microcontrollers/arm-based-processors-and-mcus/i.mx-appl...

Have a great day,
Artur

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