After a POR, when the boot process completes and the CPU starts the application, the initial device conditions are as follows:
- The NRST pin is configured in NRST mode
- Serial wire debug (SWD) IO
are configured in SWD mode (SWDIO is pulled high, and SWCLK is pulled
low)
- All other configurable I/O
pins are high impedance (Hi-Z), unless specifically noted in the device
datasheet.
- Peripheral modules are reset as described in the respective chapters of this manual
- The device is in RUN mode
- MCLK is sourced from the internal SYSOSC at base frequency
- LFCLK is sourced from the internal LFOSC (note that LFOSC requires time to start up before LFCLK can be used)
- MFCLK is disabled
- SYSPLL is disabled
- HFXT is disabled
- Peripherals are disabled
- Any flash sectors configured to be write protected at boot are write protected