Source for the routing instruction

<xs:attribute name="source">
    <xs:annotation>
        <xs:documentation>Source for the routing instruction</xs:documentation>
    </xs:annotation>
    <xs:simpleType>
        <xs:restriction base="xs:string">
            <xs:enumeration value="Low" />
            <xs:enumeration value="High" />
            <xs:enumeration value="VFG0CC1" />
            <xs:enumeration value="VFG0CC2" />
            <xs:enumeration value="VFG0CC3" />
            <xs:enumeration value="VFG0CC4" />
            <xs:enumeration value="VFG1CC1" />
            <xs:enumeration value="VFG1CC2" />
            <xs:enumeration value="VFG1CC3" />
            <xs:enumeration value="VFG1CC4" />
            <xs:enumeration value="VFG2CC1" />
            <xs:enumeration value="VFG2CC2" />
            <xs:enumeration value="VFG2CC3" />
            <xs:enumeration value="VFG2CC4" />
            <xs:enumeration value="VFG3CC1" />
            <xs:enumeration value="VFG3CC2" />
            <xs:enumeration value="VFG3CC3" />
            <xs:enumeration value="VFG3CC4" />
            <xs:enumeration value="VFG0ATSCT0" />
            <xs:enumeration value="VFG0ATSCT1" />
            <xs:enumeration value="VFG0ATSCT2" />
            <xs:enumeration value="VFG0ATSCT3" />
        </xs:restriction>
    </xs:simpleType>
</xs:attribute>