26.4.3.5 User Reset

A user reset is generated when a low level is detected on the NRST pin and RSTC_MR.URSTEN is at ‘1’. The NRST input signal is resynchronized with SLCK to ensure proper behavior of the system. Thus, the NRST pin must be asserted for at least 1 SLCK clock cycle to ensure execution of a user reset.

The user reset is triggered 2 SLCK cycles after a low level is detected on NRST. The processor reset and the peripheral reset are asserted.

The user reset ends when NRST rises, after a two-cycle resynchronization time and a three-cycle processor startup. The processor clock is reenabled as soon as NRST is confirmed high.

When the processor reset signal is released, RSTC_SR.RSTTYP is loaded with the value ‘4’, indicating a user reset.

The NRST manager guarantees that the NRST line is asserted for External Reset Length SLCK cycles, as configured in RSTC_MR.ERSTL. However, if NRST does not rise after External Reset Length because it is driven low externally, the internal reset lines remain asserted until NRST actually rises.