18.6.2.3 Reset Causes and Effects

The latest Reset cause is available in RCAUSE register, and can be read during the application boot sequence in order to determine proper action.

These are the groups of Reset sources:

  • Power supply Reset: Resets caused by an electrical issue. It covers POR and BODs Resets
  • User Reset: Resets caused by the application. It covers external Resets, system Reset requests and watchdog Resets

The following table lists the parts of the device that are reset, depending on the Reset type.

Table 18-1. Effects of the Different Reset Causes
Power Supply Reset User Reset
POR, BODVDD, BODCORE External Reset WDT Reset, System Reset Request
RTC, OSC32KCTRL, RSTC Reset - -
GCLK with WRTLOCK Reset - -
Debug logic Reset Reset -
Others Reset Reset Reset

The external Reset is generated when pulling the RESET pin low.

The POR, BODCORE, and BODVDD Reset sources are generated by their corresponding module in the Supply Controller Interface (SUPC).

The WDT Reset is generated by the Watchdog Timer.

The System Reset Request is a Reset generated by the CPU when asserting the SYSRESETREQ bit located in the Reset Control register of the CPU (for details refer to the Arm Cortex Technical Reference Manual on http://www.arm.com).

Note: Refer to the TRST specification in the Power Supply section of the Electrical Characteristics chapter.