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MPR121 very slow startup

Question asked by Gora Edouard Gabriel on Jul 9, 2015
Latest reply on Jul 13, 2015 by Cong Sun

After initialization process, the MPR121 is operational only after 1 minute or so. Reading touch registers will output zero and no interrupts are generated.

Our initialization procedure is as follows (pseudo):

 

1) set filters, from MHD Rising -> FDL Touched

 

Btw, the NHD Amount Touched, NCL Touched and FDL Touched we send = 0 since are completely undoccumented in your pdfs.

 

2) set thresholds as desired for all 12 elements

 

3) optionally set the AUTO-CONFIG registers (no difference, slow startup in either case)

 

4) set CDC, CDT and ECR

 

The following questions appears:

 

- why is this happening?

- how can we detect initialization is complete, we have a keypad designed which is not operational in first minute

 

Best regards,

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