Message Oracle RMAN-06062 - can not backup SPFILE because the instance was not started with SPFILE

ERRORcan not backup SPFILE because the instance was not started with SPFILE
CAUSEA backup command requested a backup of the SPFILE, but no SPFILE was used to startup the instance.
ACTIONCreate an SPFILE and re-start the instance using the SPFILE or modify the command.