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K82: LLWU_SetPinFilterMode() API

Question asked by Eugene Hiihtaja on Jan 9, 2019
Latest reply on Jan 24, 2019 by Robin_Shen

Hello !

 

Could you clarify a bit what LLWU filter means ?

 

As input it has structure llwu_external_pin_filter_mode_t

what has parameter

 

typedef enum _llwu_pin_filter_mode
{
kLLWU_PinFilterDisable = 0U, /*!< Filter disabled. */
kLLWU_PinFilterRisingEdge = 1U, /*!< Filter positive edge detection.*/
kLLWU_PinFilterFallingEdge = 2U, /*!< Filter negative edge detection.*/
kLLWU_PinFilterAnyEdge = 3U /*!< Filter any edge detection. */
} llwu_pin_filter_mode_t;

 

But edge detection is set by LLWU_SetExternalWakeupPinMode() API.

 

in RM , chpter 19.5 I can see

"

The LLWU implements optional 3-cycle glitch filters, based on the LPO clock. A
detected external pin is required to remain asserted until the enabled glitch filter times
out. Additional latency of up to 2 cycles is due to synchronization, which results in a total
of up to 5 cycles of delay before the detect circuit alerts the system to the wakeup or reset
event when the filter function is enabled. wakeup detect filters are available for selected
external pins. Glitch filtering is not provided on the internal modules.

"

 

How setup proper filter for LLWU pin ? I use LLS3 low power mode if it any difference with other low power  modes.

 

Regards,

Eugene

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