Have a question concerning specifically the STM32F479 NRST pin, but this may be applicable to other STM MCU’s as well. Is this Pin an Input/Output pin ?

[JMcHA]

 I read in section 6.2.1 of the STM32F479 reference manual that this Pin will Output a 20us reset pulse during Watchdog and other internal events. I did not find any Output characteristics for NRST and the statement in section 6.2.1 was stated almost in passing. So I wanted verify that I am interpreting this info correctly that it is Input/Output.  

[waclawek.jan]

There are many parameters which are unspecified for the STM32s hardware.

NRST has internally an open-drain transistor which pulses upon "internal" reset sources such as watchdog resets. You are not supposed to pull it up hard externally, e.g. you shouldn't use a push-pull-output external reset circuit connected directly to NRST.

JW

[JMcHA]

Thank You JW for your response. My intent is use something like a Schmitt trigger connected to NRST to capture the pulse event of an Internal Watchdog timer to trigger a Reset in other parts of my system. It sounds like I can do that, provided as you mention NRST does not have a hard pullup.