The NRST manager samples the NRST pin at SLCK speed. When the NRST line is low for more than three clock cycles, a User Reset is reported to the reset state manager. The NRST pin must be asserted for at least 1 SLCK clock cycle to ensure execution of a user reset.
However, the NRST manager can be programmed to not trigger a reset when an assertion of NRST occurs. Writing a ‘0’ to RSTC_MR.URSTEN disables the User Reset trigger.
The level of the pin NRST can be read at any time in the bit NRSTL in the RSTC Status Register (RSTC_SR). As soon as the NRST pin is asserted, RSTC_SR. URSTS is written to ‘1’. This bit is cleared only when the RSTC_SR is read.
The RSTC can also be programmed to generate an interrupt instead of generating a reset. To do so, RSTC_MR.URSTIEN must be set.