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Standalone application doesn't run unless NRST is forced to 0V

Question asked by Hicham Chaabane on Apr 30, 2018
Latest reply on May 2, 2018 by Hicham Chaabane

Hi guys,

 

I'm using the  STM32L475RCT in a custom board. When using the JLink everything is working fine but when I discounnect the Jlink and power cycle the board the application doesn't work at all. Each time I have to force NRST to 0 and release it in ordre to make the application works.

 

I have 100nF capacitor between the NRST pin and GND as recommended in ST  datasheet( 6.3.15 ).

I checked the voltage on the NRST pin and it seems correct : it goes from 0.358V to 3.1V  in ~4ms at board power up which follow the required low level voltage ( VIL(NRST)  =0.3ₓVDDIOx = 0.984V) and high level reset voltage  ( VIH(NRST) = 0.7ₓVDDIOx = 2.29V).

 

Any thoughts on where the problem might be ?

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