code: def swo_enable(self, cpu_speed, swo_speed=9600, port_mask=0x01):
          
          if self.swo_enabled():
              self.swo_stop()
  
          res = self._dll.JLINKARM_SWO_EnableTarget(cpu_speed,
                                                    swo_speed,
                                                    enums.JLinkSWOInterfaces.UART,
                                                    port_mask)
          if res != 0:
              raise errors.JLinkException(res)
  
          self._swo_enabled = True
  
          return None
docs: Enables SWO output on the target device.
  
          Configures the output protocol, the SWO output speed, and enables any
          ITM & stimulus ports.
  
          This is equivalent to calling ``.swo_start()``.
  
          Note:
            If SWO is already enabled, it will first stop SWO before enabling it
            again.
  
          Args:
            self (JLink): the ``JLink`` instance
            cpu_speed (int): the target CPU frequency in Hz
            swo_speed (int): the frequency in Hz used by the target to communicate
            port_mask (int): port mask specifying which stimulus ports to enable
  
          Returns:
            ``None``
  
          Raises:
            JLinkException: on error