5.3 NRST Pin

The NRST pin is bidirectional. It is handled by the on-chip Reset Controller (RSTC) and can be driven low to provide a reset signal to the external components, or asserted low externally to reset the microcontroller. It resets the core and the peripherals, with the exception of the Backup region. There is no constraint on the length of the reset pulse, and the RSTC can guarantee a minimum pulse length. The NRST pin integrates a permanent pull-up resistor to VDD3V3 of about 100 kΩ. By default, the NRST pin is configured as an input.