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What is best way to put FlexBus addr lines in high-impedance state when sleeping?

Question asked by James Vasil on Jan 28, 2015
Latest reply on Jan 29, 2015 by xiangjun.rong

We are using the flexbus of a MK24 to drive a display.  When we go to sleep, we have to cut off the power to the display module.  Therefore, we need to make sure all the pins that are configured as outputs to this device are disabled (or put into a high-impedance state) before we turn off the power.  Is there an easy way to do this using PEx?  We are using the Init_FB component in PEx 10.4 to configure these lines but it doesn't support any methods other than the Init call.

 

One idea I had was to simply change the PORT_PCR_MUX of these lines to 0 but I am unsure if that disables the pins when the ALT0 cell in the "Signal Multiplexing and Pin Assignments" table in the K24 Reference Manual is blank.  Although this table says that the "default" setting of these pins is "disabled", it does not say that you can disable the pin by setting the PCR MUX to 0.

 

A second approach I have considered is to reconfigure these pins as GPIO inputs.  One way to do this from PEx would be to have two sets of "Init_GPIO" components--one that configures the pins for sleep state and one that configures for the running state.  Would there be any problems with having multiple Init_GPIO components defined for the same GPIO Port?

 

The final approach I have considered is ignoring PEx and just writing functions to configure these lines as needed.  I can certainly do this but dislike the "mixed" approach (i.e. some configuration done by PEx and some by user-written code).

 

Any ideas, examples, suggestions, etc. will be appreciated!!

 

Thanks,

James

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