The maximum clock frequency that can be used with the internal oscillator is 32 MHz, but it's recommended to use a clock frequency of 24 MHz or lower to ensure reliable operation.
The watchdog timer can be configured using the WWDG_CR register. You need to set the WWDG_CR_WDGA bit to enable the watchdog timer, and then set the WWDG_CR_T bit to set the timeout period.
The BOR circuit is used to reset the microcontroller when the supply voltage falls below a certain threshold (typically 1.9V). This helps to prevent the microcontroller from operating erratically or unpredictably during power-on or power-down sequences.
The ADC can be used by configuring the ADC_CR register to select the channel, set the conversion mode, and trigger the conversion. The ADC_DR register contains the converted digital value.
The maximum current that can be sourced or sunk by the GPIO pins is 20 mA. However, it's recommended to limit the current to 10 mA or less to ensure reliable operation.