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 ?