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False Key Detection in ADP5585

Question asked by Padma on Mar 4, 2015
Latest reply on Mar 6, 2015 by RSchnell

HI all.,

We are facing a false key detection on our product. We are using the Keypad Decoder ADP5585 IC for the KEypad logic on our product.

 

The datasheet of ADP5585 specifies that a Key press will be detected after a key scan during which the columns will go high and there will be a minimum of two cycles of polling.

Capture.PNG

 

 

The same behavior is observed on the  corresponding column line when a key is pressed manually as shown in the figure below.

In this figure, we can clearly see that the column goes high followed by key scan.

tek00001.png

 

 

 

Whereas, during a false key detection, we do not see a key scan on the column line(as shown below).

But still, the FIFO records key press and key release even without a key scan occurring on that particular column line(as shown below).

tek00000.png

 

 

How does the FIFO value get updated without a KEyscan??

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