code: def cpu_speed(self, silent=False):
          
          res = self._dll.JLINKARM_MeasureCPUSpeedEx(-1, 1, int(silent))
          if res < 0:
              raise errors.JLinkException(res)
          return res
docs: Retrieves the CPU speed of the target.
  
          If the target does not support CPU frequency detection, this function
          will return ``0``.
  
          Args:
            self (JLink): the ``JLink`` instance
            silent (bool): ``True`` if the CPU detection should not report errors
              to the error handler on failure.
  
          Returns:
            The measured CPU frequency on success, otherwise ``0`` if the core does
            not support CPU frequency detection.
  
          Raises:
            JLinkException: on hardware error.