Electronic organ with free-combined keys and a method to realize free combination

A method to realize free combination of electronic organ keys of an electric organ with free-combined keys comprising a host processor and several key groups, wherein the key groups comprise several keys, a first interface that provides access to a host processor or a previous key group, and a second interface that provides access to a next key group, the method including the following steps:

• connecting freely combined key groups to the electronic organ;
• obtaining the number of the key groups, address information and locations of keys in key groups by the host processor;
• and
• setting the function or scale for each key according the number of key groups, address information and locations of keys in key groups by the host processor;
• wherein
• the host processor sends instructions including group number information to the key group connected to the host processor via a port line;
• after the key group connected to the host processor receives the instruction from the host processor, the key group connected to the host processor adds a value of 1 to the number information to create a modified number information and sends the modified number information to a subsequent key group, and each subsequent key group adds the value of 1 to the modified number information received from a previous key group and sends said number information to a further subsequent key group until reaching the last key group;
• the last key group recognizes itself as the last key group, then replies its group number to the immediately previous key group;
• every key group replies to the previous key group with the instruction with group number information indicating the number of the last key group;
• and
• at last, the host processor receives the instruction with the group number information indicating the number of the last key group in order to recognize the number of key groups that are connected to the electric organ.