A. The
XRSn pin can be driven externally by a supervisor or an external pullup
resistor, see
Pin Attributes. On-chip POR logic will hold this pin low until the
supplies are in a valid range.
B. After reset from any source (see
Reset Sources), the boot ROM code samples Boot Mode pins. Based on
the status of the Boot Mode pin, the boot code branches to destination memory or
boot code function. If boot ROM code executes after power-on conditions (in
debugger environment), the boot code execution time is based on the current
SYSCLK speed. The SYSCLK will be based on user environment and could be with or
without PLL enabled.