A system and method for narrow groove welding is provided. An active load circuit includes a first load device electrically connected between the data line and a voltage source wherein an electrical resistance of the first load device is varied responsive to a voltage level of the data line. Synchronization among each computing module is recovered by adjusting timing of a response to an access which each processor executes by an interruption. The data storage controller, for each received amount of data, receives the identity portion of the amount of data and performs a storage operation based on the identity portion. When a scanning test is executed, a scanning test clock signal is asynchronously input into the flip-flop groups in a predetermined sequence to form a clock signal of the flip-flop groups.