FreezeIo issue

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DaHu_285096
Level 5
Level 5
10 likes received 250 replies posted 100 replies posted

 I have a low power application that is drawing too much current when connected to another IC and placed into Deep Sleep.

   

If I measure current of each IC independently, the micro is drawing 19uA and the other IC 8uA when in deep sleep.

   

If I have both powered together (even though the interface pins are not active), the current jumps by additional 50uA.

   

When I issue CySysPmFreezeIo() before deep cleep, the current drops right down below 19uA with both ICs connected. But, the circuit does not operate correctly and if I attempt to debug then I loose coms with MiniProg 3 when freezing the IO.

   

It appears when the the IO is frozen, it now longer gets woken from Deep Sleep (I am using an IO pin to wake from sleep).

   

I copied the IO freeze example from the PSCOC4200 GPIO document.

   

Do I need to add a delay or something after Unfreeze before using the pins? 

   

Also, I have set the IO pins to High Impedance Digital for inputs and Pull Down Resistive for outputs, I assume this is the lowest current option ?

   

BTW: I am not worried about powered up current as it only operates for less than 100ms and back to sleep, it is the deep sleep current I want to reduce.

   

Thanks

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ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

From    

   

 

   

         

   

http://www.cypress.com/?rID=78797     AN86233 - PSoC® 4 Low-Power Modes and Power Reduction Techniques

   

 

   

 

   

 

   

 

   

 

   

    

   

          

   

http://www.cypress.com/?rID=93401     AN86439 - PSoC® 4 - Using GPIO Pins

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