Step into a line of source code.
Resume execution of the active target until control reaches instruction that belongs to different line of source code. If a function is called, stop at first line of the function code. Error is returned if line number information not available. If
<count> is greater than 1, repeat
<count> times. Default value of count is 1.
Nothing, if the target has single stepped. Error string, if the target is already running or cannot be resumed.
An information message is printed on the console when the target stops at the next address.