RESET_B pin release status with a slow rise time on this pin

[IvesCHENG]

Hi :

I would like to check a scenario in the RM for device ( s32k1 )  boot.

25.3.3 Boot sequence

• When flash memory initialization completes, the RESET_B pin is released. If
  RESET_B continues to be asserted (an indication of a slow rise time on the
  RESET_B pin or external drive in low), the system continues to be held in reset.
  Once the RESET_B pin is detected high, the core clock is enabled and the system is
  released from reset.

So if a slow rise time happened (probably caused by a big value of pull-up resistor on reset line).

what is the device behavior? (does it still hang until the RESET_B rise to high? any possible that device stuck on a very big rise time?)

Best regards

Ives CHENG

[danielmartynek · Accepted solution]

Hi @IvesCHENG,

Either way, whether the pin is held low actively by another device or the voltage on the pin is slowly raising while the capacitance on the line is being charged, as long as the reset_b voltage stays below 0.7 * VDD (DS, Table 18, V_IH), the MCU detects reset_b LOW and it stays in system reset.

Regards,

Daniel